Start: "How tough will it be to run 100% on propane until proper repairs can be effected?"
Do you own a DVM or VOM? Check continuity on the heater.
I would suspect that if the board was blown, the heater may have taken a hit too.
If I'm not mistaken, replacing the electric heater involves disassembling the gas burner and chimney.
TT 2015 19RD "TheJayco"
TV 2003 F-350 "Montblanc" - Housebroken chore truck
Sitting in The Cheap Seats.
And proud of it!