Did the prep work in the basement but haven't started it up yet (my garden hose keeps freezing overnight). Maybe this weekend.

A careful first-hand look at the engine and it's pretty easy to see how it could be converted to run duel-fuel with LP gas. I'd feed the LP line through spaces near the handle without drilling, and connect it at the carb intake manifold without changing anything permanently, except perhaps the silencer box (there's no air filter, just a plastic box with metal mesh at the intake). I could test it first using the crankcase rebreather fitting. That project will wait until after I do the break-in procedure on gasoline.