We went on a safari in Tanzania as well, around the same time cookiemom, but it was pre-kids.
We had a great time, the company we (DH and I) went with plans your safari for you, based on what you want to see and how expensive you want it to be. The best part was that if there was noone else interested in the same things at the same time, you go by yourself! So, we ended up with a private safari to the Ngoro Ngoro crater and the Serengeti with a driver and a cook.
It was fabulous - we could stop where ever and when ever we wanted, we saw a new born wildebeast take its first steps and a ton of other new born animals the whole time. Our driver was so knowledgable and loved that we asked a bunch of questions.
I would think it would be easy to do a unit on that area, especially if you add in the Olduvai Gorge and the work of Louis and Mary Leakey.
Have a great time planning and going - I'm hoping to do something similar with the family in a few years when DD2 is older.
