Hi hbski,
No, I've not had occasion to repeat the situation.
I do know I can run the air conditioner from the battery bank/inverter. I did that for an hour on Sunday. I was not comfortable with the DC voltage at idle when I returned to the RV, so in future I'll turn off the roof air before I start the engine.
I'm finding that I can cool the rear of the class C by running the dash air with the fan only setting on the roof air. I do have solar which provides about 1/2 the current needed for the fan only setting--and the alternator provides about 9 amps as well.