No power dry camping

Ah, no 12 volt suggests that the place to look starts at the battery. I know you said "battery is fine," and I don't mean to insult your intelligence, but I had a battery go bad on me that tested "fine" with the volt meter. It showed 13+ volts, but it delivered no amps. I took it to the auto-parts store where they put it on a load tester, and although it showed 13+ volts for them too, as soon as they applied a load, the voltage fell to zero. Take the load off, and it was back to 13+ volts. So unless you've already had it tested under load, you might consider doing that. Auto parts places will do it for you for free, as they expect you'll buy a battery should it be bad.

From there, it is a matter of following the wires with a volt meter in hand. Could be switches, or fuses, or circuit breakers. Could also be a wire some rodent munched on.