What about going to Mwanza? The runway is much longer than Arusha. It is much closer to the Serengeti. There is an approach at the airport. Fuel, customs, everything you need there. Arusha would be a bit tight for a bizjet. Kilimanjaro has everything that Mwanza has and more but again, is that much further from where you want to be. The only advantage really in going through Arusha is that all the other parks that Tanzania is famous for would be on your route and the safari industry is far more developed there.