You should have used the genset, Stan. Charging low batteries with the engine alternator is a good way to ruin it, as several threads on this forum have explained. It should be the house batteries that run the fridge. It is likely also that the gas valve didn't turn on at the tank if the batteries were down.
The gas valve, burner ignition, and most if not all fridge control circuitry are 12 v. If you have an ice maker on the fridge, that is AC.
If you park the rig where it has no solar battery upkeep or AC available, then turn off master battery switches before leaving it, and always use the genset, not the engine, when you return, even if you have to use the boost switch or portable jump unit to start the genset.
Joel