Self Drive Namibia/Botswana/Victoria Falls - Need Advice

My husband and I are planning to do a self drive tour in Namibia including Botswana and the Victoria Falls starting June 1st (3 weeks total). We are currently planning the itinerary. I know that we don't have much time left to plan the trip, Is it advisable to book accommodation in advance for June? I heard that it is a must to prebook for Etosha. We were thinking of renting a 4x4 with camping equipment. Is it necessary to book a campsite in advance? If anybody could recommend a rental company, that would be wonderful. I would be grateful for any tips. Thanks!

When we visited in May campsites were far from full, even in Etosha, but I would still pre book since I've read NWR people can react quite unreasonable when you show up without a booking, that's just hear say.

Bring or rent good sleeping bags it can get real cold in June, below freezing at night.

Don't plan on to long drives, you have short day light hours that time of year, sunset will be around 5:30 pm, after that your not allowed to drive a rental car or you void your insurance, max. speed on gravel is 50 mph stick to it, rental cars have black boxes that the company will read out, specially in case of an accident.

http://www.natron.net/autose.htm here is a list of car rental agencys, we used http://kalaharicarhire.com/ it's not on the list because he rents out older cars too, but he has a good reputation, make sure you're allowed to take the car out of Namibia and have all the paperwork to do it.

Can't help with Botswana or Vic falls.

Thank you very much. This is very helpful.