I can not compare what South Africa offers (as I have not been there), but a safari in Kenya can easily give you two parks in a very short amount of time. Masai Mara (of course), and then 5 or so hours past that is Lake Nakuru. Lake Nakuru is famous for its flamingoes, but water levels rising on the lake have made them less plentiful. Very different vegetation and animals here. For both I would get a guide, I honestly would never drive there and you will see more with a guide (they know where the animals are and when, they will also keep you safer IMO). For MM, it is easy to see online which camps are inside the park, some are luxury tents, and others look like mud huts with thatched roofs. Different price points of course, it depends what level of luxury (and food quality) you're aiming for.
The second thing I love about Kenya, is the coastal area outside of Mombassa. Diani beach is especially pretty (a little South of Mombassa). It would be easy to combine a safari and coastal trip here. There is only one timeshare in Interval for Kenya, located near Malindi (the coastline North of Mombassa) -- it is a 4* star hotel.
Good luck on your travel plans and congratulations on your upcoming anniversary!