Since it sounds like you haven't even bought the trailer yet, here's something to muddy up the waters......How about a Class A motorhome? That way everyone's not crammed in their individual little spaces in a crew cab truck, and you're not having to face some of the issues mentioned with using a full-sized van as a tow vehicle. Start your adventure when you start the engine -- not when you arrive at your destination.
Now, that being said, if the trailer is your one and only option, I guess I'd opt for the full size van as a tow vehicle, but with your crew, the Class A seems like the best choice (to me). Do what's right for YOU!
Happy travels!
