First things First
Chimba Warrior is on track. Market research coupled with the aircraft limitations or a must - then start with the wish list. B767-200F is the wrong aircraft for a starter. Note the yield out of SAMEC will have to be sufficient to contribute to the return leg. SAMEC to West Africa prime markets will be PHC / LOS / LAD / SSG. However these destinations are useless for the return leg. You will have to bounce the aircraft back via ACC or DKR for return Fish & Veggies. There is nothing else. If you wanted to go across to Middle East after offload West Coast. Again only veggies a fish. DXB back via Africa to Mid West US ? No idea.
Start with the right aircraft. B747F-BCF.
I smell a under graduate doing a logistics thesis ? If not. God help your investors.