Thank you all for the comments.
BFL13 - I got the generator started with a dead battery by turning on the RV engine; l the generator kicked right on. I didn't do anything different getting ready for the trip. Just turned the lights on and then noticed that they were starting to quickly go dim again.
Several of you mentioned the converter. Forgive my ignorance but is this the same as the inverter? I have an electrical box with fuses and circuit breakers that controls everything in the coach and my understanding is that this is the inverter. It failed 2 years ago and I had it replaced.
I will start by having my coach battery tested as you suggested.
Thank you all so much!