THAT is a classic! I think you should buy it immediately!
I owned several of those Dodge Power Wagons, mid to late '70's, over the years, both half and 3/4 ton. Every one had 16 inch tires. It is a good bet that one does, too.
As for the 360, the only thing to keep in mind is that the "silent chains" that Dodge/Chrysler used back then for cam timing had plastic teeth, and when the plastic got worn and/or brittle, it could fail (usually at the worst possible time/place) and the cam timing would jump. That usually resulted in valve damage (interference engine). For anybody who has the proper tools, and some mechanical ability, replacing the chain and sprockets is not difficult. Make sure the new chain does NOT have the plastic coated teeth. In fact, it might pay to look for roller chain and sprockets. There might even be a gear drive kit available.
Most 360 engines in camper/motorhome applications came with 4V carburetors. that carb and manifold is nearly worth the asking price!