Back on the Propane, I have decided to go with standard bottles like those found on most cooking grills. Two of them should fit nicely in where the Gas Tank is, which means going in through the trunk. Never realized the trunk was made of wood before, though. Looks like this trunk has seen it's better days anyhow.

The Trunk finally out, the Gas Tank is the next obstacle. A little bit of a bear here. Four bolts on top, simple enough, other than having to remove one of the rails that held up the trunk, to get at the last bolt. The fill tube did fit out through the top after removing the seal, a little tricky maneuvering it past the vent pipe, but it fit. However the fuel line is bolted on the bottom of the tank, up inside the trunk. Suddenly someone else's cuts made sense, fold them up in and a wrench fit. Otherwise I would bet you would have to groove a side out of a socket and weld a T handle to it, to get to this fitting.

The Gas Tank finally out, I used an old junk Propane Bottle to test fit. It's a little tight, but it is going to work. Now I just need to make a bracket to mount two tanks, and plumb them in. I could probably use the Propane Rig off an old Camper if I can find one, but it should be easy enough to make something too.