When I was in Nairobi last fall (hoping to be there again this fall, incidentally), my group stayed at the Holiday Inn, and hired a local chap as our driver and "coordinator." He'd come by each morning with the car to pick us up, take us places (he'd go with us as well), run errands, et cetera. He was most helpful. I'm not sure exactly how the deal worked; I think it was sort of renting a car, but with a driver included. Very nice fellow. But that level of service was, I'm sure, somewhat more pricy. I believe they probably spent close to $1000 a week.

(By the way, the restaurant "Peppers" down the street from the Holiday Inn was quite good, in my opinion.)