When is the last time you drove opposite side? and do you plan on doing any day trips outside the city? If you're not doing any day trips outside the city just stick to Uber. You can probably get anywhere you need to go for less than $6 a trip. so to me, the hassle of city-driving, finding parking, some streets narrow as hell like more narrow than some DC blocks. uber is just way more convenient especially given the price. in SA with that exchange rate you will feel like a king.
I think last time I went Nov 2016 it was around 13 to 1. food and drink will be stupid cheap. only thing pricey may have been day tour type stuff, where they pick you up at your hotel/airbnb and go somewhere for the entire day, but that's normal in any country.
Nairobi is different. especially in Westlands. Westlands is the prime spot for wealthy Kenyans and expats, so even though the exchange rate is good, things are more expensive there. Everything is priced in knowing that most folks got American/Euro paper. Outside of Westlands things get cheaper. Theres this one spot for nyama choma called Njuguna’s. this is a very popular locals spot. straight up hole in the wall type joint where ya uncles and dad would come to watch the game on a lazy Sunday afternoon drinking guiness all day. I was there with this one chick and we saw one of the presidents people walk in with his bodyguards after the inauguration. was pretty dope. since you not doing Mombasa you should probably be good with 1k for week in Kenya.
between the two I wouldn't be surprised if you had some cash leftover after SA.