2000 Bounder electrical shutdown

Check every battery connection and not just the ground side. Just looking at them will tell you nothing.
That means taking them apart, cleaning and reassembling.
It can also be the battery shorting internally. If it's old, replace it.

Clean and tighten your battery terminals. It's easy and quick.
Then you know you have a good connection before you start your diagnosis.

A little corrosion on the terminals, that you can't see, gives me starting problems on our 96 Southwind.

Could also be a loose/short wire on the ignition switch. Electrical gremlins are a PITA....Dennis

Thanks all. The battery is new, I cleaned and checked all the connections.
I'm starting to think it could be the ignition switch.
I noticed that it usually occurs when I hit a good sized bump in the road.
Maybe a wire internally in the ignition is loose.
Back to the drawing board.

Jiggle the wires around with ignition on, engine off and see what happens.

With the engine running, chances are it's not the battery connections themselves as the altenrator can provide power sufficient to keep the engine running in most cases even without a battery (not that it's recommended to operate that way, for several reasons). I actually have some personal experience with that; I had a car decades ago where one of the battery lead clamps was worn/loose and would occasionally vibrate out of contact. The headlights would dim and the wipers slow as one came to a stop and the engine idled, and then get back to normal-ish when moving along again. When one reached the destination and turned the key off, only then would everything go completely and eerily quiet and dead.

Ignition switch or wiring harness, dashboard ground, that sort of thing would be my guess, as others have suggested.