My family did this when I was a teen, though I was mostly shooting Hi8 video (for which the main challenge was electrons[1], staying still in uncomfortable positions for prolonged periods, and field-servicing the tape mechanism when it jammed). My dad got some lovely stills on 35mm film with a 170-500mm.
I'd suggest you want 400mm upwards, unless the critters are particularly well trained. (You can get surprisingly close in a vehicle, as they don't consider them a threat, but the interesting stuff is always *over there*.) See if hiring a big lens is an option?
Teleconverters are handy (if only for the obligatory sunset shot), but be aware that wildlife is most interesting around dawn and dusk, so you won't necessarily have oodles of light. If you'll be venturing out after dark a powerful flash is worth having, but don't expect miracles.
Monopod is the thing to use for the back of the Landcruiser, though a tripod's worth having too.
The 24-70 on a second body sounds like a good idea.
Bring plenty of lens cleaning supplies and some jeweller's screwdrivers.
Practice your manual focussing, there will be undergrowth in the way.
Don't leave your delicate tape mechanism in a black camera bag in direct sunlight for an hour.
Don't black out from hyponatraemia just as you close in on an elusive species of antelope, or if you do, make sure you switch back to full-auto first so whoever takes the camera doesn't just film a couple of leaves with antelope-shaped bokeh.
Don't photograph interesting insects by the light of a head torch. They may have wings.
[1] I smuggled 6kg of AAs past the luggage weigh-in at Heathrow, which helped.
