I like solar. When I check my battery meter and it shows that my batteries are fully charged I'm a happy camper!
I put a lot of info re: solar in this post:
http://classbforum.com/phpBB2/viewtopic.php?t=712
It's a two page thread.
If you need air conditioning to cool your van down then you'll need to run your generator.
With a B van you probably have to move every few days to empty waste tanks and get fresh water. That'll put a bit of charge in your house battery(ies).
The high cost of solar is its only drawback. For a single trip it's not worth it. If most of your camping is with
no hookups then it's worth doing.
Solar is the only way my batteries get to a fully charged state because my converter only puts out 13.8 volts (or 13.6 - I can't remember which right now). The Chevy alternator might do it also but I haven't measured the voltage at the house battery to know for sure.