Just got back from Kenya and would recommend Mount Safari's Adventure http://www.mountsafaris.com
I booked everything with Jeremiah and he helped customize my trip and was extremely flexible.
We went up mt kenya on the chogoria/sirimon route and for the safari we did 3 days in Masa mara,
3 days was just enough and we saw almost every animal.
Everyone with the company was very professional and I highly recommend looking them up if you are heading to Kenya.