I have access to a standard gym in Africa, and will be here for one year. What program or combination of programs would provide the largest physique changes for when I return to the states?
Heavy compound exercises, e.g. squats, deadlifts, pullups.., are always good for building mass. Depending on your progression it makes sense that you do a full body workout (squat/lift, pushing and pull on every training day) or a split (1 day push, 1 day legs, 1 day pull).
Optionally you can add isolation exercises in order to remove imbalances.
And remember: Never skip leg exercises.