Is the Eritrea/Ethiopian border really still closed to airways traffic these days, that Lear business was about fifteen years ago and nothing's been shot there since
afaik. The military conrontation there is over, surely?
Very much doubt there is avgas in Dire Dawa, though there will be mogas at local petrol stations. DD is a thriving and pleasant town but the airport is surrounded by big terrain.
Echo the comments re Djibouti.
I assume a route through Sudan (Khartoum) is not feasible? Avgas may be possible at Lokichoggio - piston types probably still operate there from Wilson? Or is airspace closed between N and S Sudan?