Yep, that took care of it. Not sure what goes wrong inside a switching valve/regulator, but the store where I bought the replacement said they put a new one on every pre-owned unit they sell.
So back to getting ready for trip South in two weeks. Hope to not need furnace much for a few months, but you never know. We have found, between our fireplace and an add-on Edenpure heater, we can avoid spending a lot on propane most of the time.
Thanks so much to everyone who commented!
Y’all be safe traveling, and help the other guy be safe along the way. God bless
David