MiniVans will not accomodate weight well, if you are going to be packing gear, people. It's the equivalent of a 1971 VW Bus fully loaded: slow for you, very hard on the engine.
Cargo vans are the next step up. Commercially, the Chevy Vortech engines are the best thing going, but other options I pursued over tha last 3 months are:
Mercedes Cargo Van (very rare)
Ford diesel (5.9 liter, I think, but still ~20-22 MPG, and they call it the 500,000 mile engine). Price is escalated for the diesels by 2-3000 dollars.
The Park and Sell was inflexible and not invested in their clientel, in my experience. I went through an established local dealership, as I could not find them on private party listings ( but I AM in Bellingham.
Hope my research helps!
sickie E