Where to go on 10-day self-drive safari??

Spouse and I are currently in Eldoret working, and plan to go on a budget safari in about 3 weeks. I looked at a variety of camping safari outfits but ultimately settled on hiring a car and driver for 10 days to give us total freedom. We have our own camping gear and are happy to stay in primitive campgrounds, although a toilet and shower are always appreciated. We're leaving from the Eldoret area so sights in Western Kenya would be convenient, if we only knew of them. We'd like to minimize drive time between parks so most of our time is spent looking for animals. Our only absolute requirement is at least 5 days of game drives in Masai Mara, where we'll probably stay in public campgrounds. Otherwise, please share suggestions on how to fill our other 5 days!