Van will not Move

Anything is repairable. The issue is determining what actually failed, and the costs of repair.
From the description it's hard to give you a "replace this part to fix it" answer. That said, it sounds like it may be a broken one way clutch inside the transmission. It would mean either a rebuild or a used transmission if that's the case.
It also could be that it's something outside of the trans like a failed axle shaft or CV joint. If that's the situation it would be much less money. Without seeing it myself that is about as far as I can advise. You would probably be better off to have it towed to a shop and let them look it over to physically see what failed.

The gas smell could simply be that the gas sloshed in the tank and some made it out the tank vent into the vent line.