Update - appeared to be dead house batteries
After charging the batteries all night via the onboard charger, I still only got the clicking sound from the generator.
I started up my coach and let it idle in the driveway for close to an hour while we loaded it.
As we got ready to go, the interior lights came on and I had electricity.
The generator fired right up.
Clearly I depleted the batteries, and probably damaged them.
But we're on our trip and everything seems to be working.
Thanks for all the help/suggestions.
2015 Georgetown 27S