I researched Marine Corp bases in Africa/Asia and there are some possibilities: Djibouti and Kuwait are the only possibilities. Also I looked at Europe and found Germany has a US Marine Corp reserve in SW Germany in city called Boblingen, which is kind of near Stuttgart. Airlines flying out Djibouti is also simple since Kenya Airways, Air France, and Ethiopian Airlines is has good majorities of flights to larger cities that connect to Dubai. Kuwait is also good, but they visited Kuwait in Season10. As for Diego Garcia mentioned in a different post, military aircraft would be the only way to get there and they would never actually get to go there anyway.