Can you recommend any safari locations you can reach by road from Nairobi instead of flying?

Yes! There are lots, here's a few that I'd recommend:

• Nairobi National Park and David Sheldrick Wildlife Trust – 30 minutes from the airport!
• Lake Naivasha, Cresent Island and Hell's Gate – approx two hours
• Lake Nakuru National Park – approx three hours
• Soysambu Conservancy – approx three hours
• Aberdare National Park – three to four hours
• Ol-Pejeta Conservancy – four hours
• Amboseli National Park – four hours

You can get to the Masai Mara and Tsavo East/West by road, but they're both closer to a six hour drive. But you could break up the journey with a stop at one of the above locations on the way. Most of our itineraries are road based and work this way.