The map you create for the kills is going to very specific and will work for all of the achievements.
First of all, the island is going to be very small. Make a horseshoe out of trees for trapping purposes to cover the back side.
Litter the ground in front of the trees and between the beach (maybe 30-40 feet) with feral potions and grenades.
I created two rows of feral potions and grenades, and put an ATV at each end for the vehicle kills. You can usually back up into them and get the kill.
On the opposite side of the island, which is very close, stack shipping containers and place next to them a very high watch tower. Be sure to rotate and float items to get jumping areas and place a feral potion on each box.
Up top there is going to be just sniper rifles and ammo for them.
Congratulations! You have made the perfect boosting map. Remember to keep the map small!