I agree that heat could be an issue in April although it varies until later
in the year when it becomes full-time, ridiculous hot.  I grew up travelling
and camping in many westies from a homebase in the Mississippi Delta and
have camped in most of the states that you will visit.  The two most
important things to plan for in my opinion are the heat and the bugs.  You
will also find that many areas in the deep southeast don't offer a lot of
camping options.  I always prefer free and scenic campsites but often have
to stay in pay campsites while travelling down here.

12v fans work well in the southern, humid heat for both cooling and keeping
the bugs off.  With a deep cycle battery and a couple of the small, high
speed fans you and your friend should be able to bath yourself in moving air
at all times.  Be sure to repair all of your screens.  There are lots of
other tricks that I employ to ensure deep-south summer comfort including
planning to spend the heat of the day in air conditioned or wet spaces
(museums, libraries, cafes, beaches, lakes etc.),  letting the engine cool
before getting in the lower bunk, pointing the top into the breeze and
opening the rear hatch (screened of course), keeping the interior as clean
as possible to minimize bug attraction (don't store/cook fish in the van if
possible) etc. etc...  As long as you have the fans and a good battery you
should be o.k. April is one of my favorite times of year down here.

If you are interested in civil rights you gotta go hang out in the
Mississippi Delta,, Greenville, Clarksdale, Rosedale, Friars Point, etc. the
Delta is a very unique place.  I won't go into to it as it would take an
even longer email to try to explain but be sure to spend a few days
there and plan ahead as you don't want to camp just anywhere as that could
be dangerous!(crime is high in most of the towns)

Jonathan Poole
'82 AC Westy