They make some now that are just oversized duffle bags on wheels, so when you get them down from the top of the van, you can roll them where you want them to go. When they're unloaded, you can fold them back down and put them in a closet or under a bed! Clothes and lighter weight items would be great in these cause they wouldn't be so heavy lifting up and back down. They hold quite a bit of stuff. Saves room to put the heavy stuff inside the van.
Check out post #7 on this thread. It's cute
http://www.freerepublic.com/focus/f-chat/1331709/posts