Thank you all for the detailed diagnostic suggestions! I will check all the above.
The RV is parked in the driveway, so no road emergency. Its been raining for days here and looks like more days of rain, so I will have to wait to work on this thing.
I WAS wondering where the battery circuit breakers were.
BTW, I replaced the 2 highly rated original house batteries with exactly the same make/model/voltage.
The original chassis battery was a Walmart Everstart dated 8/2010. Maybe a new record for those cheapo's.
Thanks again and I will let you know status!