Personally, I would step up and plumb in a frame mounted RV propane tank, and put some armor around it. A tube like on the old VW buses will easily run your grill and a propane lantern for a few days. One for sized for a Class B motorhome will obviously last longer.
The advantage is it's hidden, protected in a crash, and out of eyesight of thieves. Since propane is heavy a leak won't flow down and pool in the vehicle when somebody is sleeping in the back. You like repeat customers, right?
On the flip side you can't just swap one out like you can a BBQ tank thrown on the rear rack. It can be quite a hassle finding a place to fill it while on a trip. Maybe a hybrid of some under frame hidden coleman tanks that you can pick up at the local Walmart no matter what town you're in would be the solution.
Of course, I can't find my links to a manufacturer I'd been looking at, but here's a pic of a similar style on thesamba:
http://images.thesamba.com/vw/gallery/pix/793075.jpg
The advantage is it's hidden, protected in a crash, and out of eyesight of thieves. Since propane is heavy a leak won't flow down and pool in the vehicle when somebody is sleeping in the back. You like repeat customers, right?
On the flip side you can't just swap one out like you can a BBQ tank thrown on the rear rack. It can be quite a hassle finding a place to fill it while on a trip. Maybe a hybrid of some under frame hidden coleman tanks that you can pick up at the local Walmart no matter what town you're in would be the solution.
Of course, I can't find my links to a manufacturer I'd been looking at, but here's a pic of a similar style on thesamba:
http://images.thesamba.com/vw/gallery/pix/793075.jpg