Want a tow-behind, not a van. The van's all set up with my bikes and gear.
I would not want a Sprinter - all the campers based on them that I have seen are very cramped inside and they seem to rust out about a year and a day after people buy them. I think they're built with tin plated cheese.
Also, I have a female riding friend who I travel with but don't sleep with; that wouldn't work very well in a van...
Oxymoron...