This outpost is positioned in an intersection of two main roads so there’s always some random cultist vehicle driving by. Because of this, approaching the outpost from the main roads is not a good idea, especially if you’re aiming for an undetected liberation of the area. The best location to start your Assault would be the woods behind the station. If you want to have a good vantage point to tag the enemies in the gas station, you can climb up the billboard across the road and scout from there.
You can start picking off enemies from the garage side of the station and work your way from there. There are no Special cultist units in the station as well so you can throw a bait to lure predators in the area and cause havoc that you can exploit. Even small predators like wolverines will be able to take out at least a couple of cultists before getting killed.