As others have suggested, the dash ignition can go funky, as ours did long ago on our Pace Arrow. But pointed out here also was the ignition solenoid in the street side forewardmost bay, a quite common failure device. So be sure to review online its proper operation, then check that it passes clean and full 12v through as designed. It's not expensive, easily replaced, and many of us carry a spare.
Also from your description and I believe mentioned here, check your alternator output if your chassis batteries aren't fully charged after a short time on the road. Many owners break a dry camp without using the generator for awhile beforehand, and overwork the alternator to build back the house batteries, a job its not designed to do, and resulting in its being burned up.
Joel