If you are now three-up and full fuel I would have a VERY close look at the t/o performance figures. Eastern Africa is the classic 'hot-and-high' situation. Having flown Cessnas in Africa myself, I can tell you you may be in for a surprise when it comes to performance. And it won't be a positive one...
Avgas will likely be your biggest issue, no matter if the owner is relaxed about it or not, especially for the Egypt-Kenya bit.
As Katamarino has said, contact Sam, he deals with these things on a regular basis.
PS: you may also get a better idea about the fuel situation if you post your queries in the 'African Aviation' section here.