"We've received intelligence reporting Imperial activity in the area. This is your starting position. Sweep in quickly and drive their strike force back. Your objective is to occupy their base camp. Good luck."
Alicia boosted by Awoken Potential and equipped with a ZM Kar 8 or 9 (or a regular rifle and Damage Boost) can finish this map in one phase fairly easily on her own. Position her in the furthest forward southern position and run straight for the enemy camp. Take intentional damage to activate Valkyria if necessary, then take out the Heavy Tank and Shocktrooper Leader before occupying the enemy camp.
The following strategy requires the Shamrock to be equipped with its flamethrower.
This map is most easily completed in the first phase, as the enemy receives a small army's worth of reinforcements at the objective camp every turn. Place a Scout (i.e. Alicia) and a Lancer with Ultimate Anti-Armor in the furthest forward positions, and of course Rosie and Largo somewhere for CP.
To start, select your lancer and run them toward the enemy camp as far as you can to move within killing range of the Tank Destroyer. Take it out.
Next, select the Shamrock and drive toward the enemy camp while avoiding the anti-tank mines. Try to center yourself on the road. You will not be able to target any enemies during this movement.
Select the Shamrock again and move further down the road. Use the flamethrower to take out the two Shocktroopers you first come across, then continue toward the camp. It may be acceptable if one Shocktrooper dodges the flame or is missed, just have your Scout take it out from distance later.
Select the Shamrock once more and drive up to the camp. The flamethrower has a wide enough arc to take out everybody except for the two outermost Shocktroopers. Thankfully, these two units and the Snipers up in the towers are not considered to be within the camp, so killing them is not necessary to occupy the camp.
Use your remaining two CP to move the Scout into the camp for occupation.
The following strategy makes use of DLC unlockables such as the ZM Kar 8, ZM Kar 9, and the Ruhm. Other than these, all units should be level 20 and equipped with the best available Gallian weapons. It also relies on very precise actions that require luck and turn-by-turn saving and reloading as necessary.
Another disclaimer: this strategy is quite specific with regards to enemy movements, which may vary from playthrough-to-playthrough.
In the northern group, place an Engineer on the left and an Ultimate Evade Scout equipped with the ZM Kar 8 (or a spare ZM Kar 9 if you have multiple) on the right. I chose Musaad as my Scout, as his Bloodthirsty potential can allow multiple kills in one CP, but this strategy does not rely on that.
In the middle group, place Alicia equipped with the ZM Kar 9 in the center and a Sniper, preferably Ultimate Accuracy Marina in the lower spot.
In the southern group, place Largo on the left, an Ultimate Anti-Armor Lancer on the right, and Rosie equipped with the Ruhm at the bottom.
To start, select your Engineer and hug the building wall as you run towards the alley on the left with the ladder. Remove the mine in your way, then prepare to absorb some interception fire from both enemy Scouts in the front group. Don't stop running until you see a mine in the alley click, which should be far enough to avoid further interception fire. Disarm mines and climb the ladder. Shoot the Sniper there, then either hide in the corner by the ladder, or climb back down the ladder completely.
Select Rosie and sneak towards the edge of the building in front of you. Since your Engineer attracted the Scouts' attention, Rosie should be able to enter Action mode and aim for the far scout without being fired upon (the building edge protects from the near scout). The shot is tricky; 14 of 20 bullets need to hit, so reload if necessary.
Reselect Rosie and move slightly out into the street to take out the other enemy Scout. End her turn by moving back into cover by the building, but face towards the street to provide interception fire in case any of the Shocktroopers move in the Enemy Phase.
Select your Ultimate Evade Scout and head towards the northwest enemy camp. If you hug the building wall, the two Shocktroopers will not notice you. Take one out, reselect the Scout, take the other Trooper out, and then occupy the camp. Use your remaining to AP to follow the path your Engineer took earlier, except this time turn right at the rubble pile and end your turn without alerting any of the Shocktroopers.
ALTERNATE: Instead of reselecting the Scout to finish off the second Shocktrooper in the base, select Welkin and execute a Team Attack. Welkin can then be left in a safe spot and in the next step you can move your Sniper to cover instead of leaving them in the open.
Select your Sniper and take out the enemy Sniper in the tower at the far end of the map. End your turn without moving the Sniper at all. They are done for the remainder of this battle.
Select Alicia and run to the left to follow the same path the Engineer and Scout took behind the rubble pile. Continue behind the Shocktroopers without alerting them and head towards the middle enemy camp. She should have enough AP to sneak up on and take out the crouching Shocktrooper there.
Reselect Alicia and kill the Sniper right next to her. DO NOT OCCUPY THE CAMP. The enemy will waste some CP calling reinforcements during their phase. Instead, use her remaining AP to run backwards around the nearby tent to keep her safe from the tanks. End her turn somewhere in the vicinity of the little table with the radio on it, facing the Troopers for interception fire.
With all your CP used, save, end your phase, then pray. The enemy will call several reinforcements, then advance the three tanks to fire upon Welkin, who can take two tank blasts, and your Sniper, who we left out in the open to draw some fire away from Welkin. The only unit permitted to die during the enemy phase is this Sniper; if anyone else, then I would consider reloading.
One other thing must happen during the enemy phase: their ace, Ty the Immortal, must attack your Ultimate Evade Scout, who must dodge this attack and make it through the rest of the phase alive. If you moved the Scout too far into the street, they may attract some tank mortars, spelling death. I accidentally left Rosie too far in the street as well, attracting some tank fire, though this may have been a blessing in disguise since she dodged them all. You may consider intentionally doing so as well. In my battle, the other Shocktroopers did not move at all.
Select Alicia, run back towards the middle enemy camp and occupy it (she may take some tank interception fire, but she'll be fine), then return to the radio table and take out one of the Shocktroopers in front of you.
Reselect Alicia, take out the other Shocktrooper in front of you, then sneak up to Ty the Immortal (who has his back turned to you since he attacked your Scout earlier) in preparation for a team attack later.
Select your Scout, immediately enter Action Mode to take out the Shocktrooper nearest the rubble pile, then run around said rubble pile before Ty's interception fire kills you. Sneak all the way around to where Alicia is standing in preparation for a team attack.
Select Rosie, sneak up to Ty the Immortal, then execute a triple attack with Alicia and the Scout. If all bullets land, it should just kill their ace. Crouch behind a sandbag and end your turn while facing the direction of the enemy camp just past the building on the left.
Select your Ultimate Anti-Armor Lancer three times to take out the three Light Tanks in the main street, then end your turn under some sort of cover.
Select Welkin with your final CP. Move him behind the sandbags near the tent/radio table and then inch him towards the southern enemy camp (with a Tank Destroyer and some Shocktroopers) as far as he will go while remaining in cover. Make sure to end his turn while facing the direction of that camp.
During the enemy phase, they will call for more reinforcements and then attempt to move some units. However, Welkin's interception fire will halt the progress of the Shocktroopers from the south camp, while Rosie will cover everything in the main street. Oddly, the enemy will not move their Tank Destroyer, meaning Welkin is safe.
The enemy Scouts who encounter Rosie's fire will rethink their approach and then try to retreat behind the building to climb the ladder there and attack from above. If Rosie manages to hit them en route they will stop again, but one Scout may make it up to the building, in which case he will run to where the enemy Sniper used to be and shoot at someone in the main street (your Engineer will be ignored if you hid them). If this ends up killing one of your units, I would consider reloading.
The enemy also conveniently moves their Shocktrooper out of the rooftop camp and into the main street, leaving it open to occupation by your hiding Engineer next turn.
Select your Engineer, clean up any Scouts who made it up the building, then occupy the rooftop camp.
Due to Rosie and Welkin's interception fire, the enemies will bunch themselves up nicely. Select Rosie and find two units you can take out with one Ruhm attack, either in Welkin's alley or near the enemy camp past the building (preferably the latter). After doing so, use her remaining AP to advance further down the main street.
If more than one enemy remains near the Engineer building camp, reselect Rosie to take them out, then advance further down the street without taking too much interception fire.
Once only one enemy remains at that camp, select your Engineer and descend the ladder. Immediately enter Action Mode and take out the remaining enemy unit, then remove some mines until you can occupy the camp. If you have any remaining AP, make your way out into the street, repair a sandbag, crouch behind it, then face the Shocktrooper camp to help Rosie with interception fire in the upcoming enemy phase.
Select your Lancer and take out the Tank Destroyer in the south camp. They are finished for the remainder of the battle.
Use CP as needed to select Welkin (or your Sniper if they survived) and clear out the rest of the standing Shocktroopers near the south camp from a safe distance.
Once only the crouching Shocktrooper in the base remains, select Alicia and run towards the south camp while hugging the rubble wall. Somehow the Shocktrooper will not notice your advance, so you can sneak behind him and take him out at your leisure before occupying the camp.
If Rosie managed to take out two enemies at once earlier this phase, you should have one CP left. Select your Scout in the main street. They should have enough AP to reach the enemy southeast camp, which is empty (but does contain many mines). Occupy it, then end your phase.
During the enemy phase, the enemy will try to advance their Shocktroopers, but Rosie and your Engineer will stop them in their tracks.
Select your Scout in the southeast camp and use the back alleyway to sneak up on the remaining Shocktroopers, who can all be killed in one CP each thanks to the ZM Kar 8/9. Operation Complete!