The Size of the Force is desided on by the allies helping the size of the enemy force. but the US will always try to take control of a airport/runway that can handle landing of c-5's to move in m1a3's.. in the past it would be an marine force landing by sea and or by helo. as well as airborne units of the army. usual SF units will have already landed and set up some kinda post or contacts with locals.
but really situation dictats the size of the force.
but remember the current idea is to use as small as a force as possible.
most likely jsut a few 100 marines to secure a airbase then build up from there.
but you can look over all the FM's at
http://www.adtdl.army.mil/atdls.htmlyou might find something there..
but since somila the US tries to avoid at all costs to go into african conflicts. since it holds no value to them.
the french might try to sablize it since it use to be a french colonaly. but really it is up to you since you are in fact the C&C and are planning the missions.