This Outpost sits on a beach. The best chance you have of scouting it undetected rest in heading in from Mosquito Yard via boat. Head to the Northern end of the area where you find Orphan Point. This puts you in a position to approach it from the North through the cover of trees. Hug to the bushes and the trees. This will let you see the 5 Pirates (1 Sniper, 2 Soldiers, 2 Chargers) who man the outpost. You will notice there is a boat around in the area with 2 soldiers on it. Do not worry about it as they are not part of the team holding the Outpost. They are there as support and do not need to be killed.