Walking up lions is certainly doable. Leopard stalking though is a virtual impossibility, although it has been done. Your best chance for Leopard, other than baiting where legal, is following a pack of hounds. On the other hand, in the Kalahari Leopards are hunted using Bushmen trackers, while the P.H. and his hunter follow in a vehicle. When the Leopard finally holes up and the trackers and hunter get close things tend to happen fast and furious. For a first timer in Africa though, I would suggest a general plains game hunt in on of the Southern African countries such as South Africa or Namibia. Lots of game, great facilities, and generally impossible to have a bad time.