Botswana doable in April??
 

I'm guessing that by the time you get there the road from Kasane to Maun will be sealed (tarmac, asphalt, whatever you call it in Canada ;) which will help.

Thinking more of Northern Nambia rather than Bots, but aware that much of the water comes from Angola anyway, I'd say you will have some water around, at least in the parks which might prove difficult, especially in Moremi.
When to Go to Botswana | African Holidays | Go 2 Africa

But this is normal each year.... most of Botswana is sand which helps.

I can't see why you wouldn't be able to move along your route, but sometimes the interesting things might be inaccessible because of water. All part of the fun ;) Enjoy!

The Bradt guide is very good and will help with these types of questions:
Botswana - Bradt Travel Guides

Also worth getting on the email list at overland.co.za - friendly helpful people who know these areas well etc (Though mostly all South African).

Check out the Maun Self Drive 4x4 track conditions updates.

We traveled almost exactly the same route as this in April 2010. A link to our web diary is below (first entry is at the bottom of the page).

http://off2africa.synthasite.com/botswana.php

You may well encounter mud en route to/from Savuti and water is a permanent feature in many parts of Moremi now. But to answer your question yes there will be others traveling the same routes so help/advice will never be to far away. If unsure wait for someone to come along - fellow 4 x 4 travelers and game vehicles are almost always happy to help.