Would it be ok to use a marine switch to separate two batteries that
would switch everything on your van over to a different battery when needed?

Or would it be bad to actually run the vanagon with everything connected
to the aux battery?

I just figured that while camping, you could use the starter battery to
get you going, but after a night of camping, switch over to the aux
battery during the following day of driving, so you can fully charge it
again before the next night of use?

thanks for any tips!

cr