Check with CC for a drawing of the AC electrical routing. There may be more than one GFI in the circuit so check them all.
I had a mostly dead side once and it turned out to be a open circuit in the Patio outlet. I never would have checked there myself (because it was outside - out of sight, out of mind), someone on this forum sent me in that direction. And first off, it measured 120 V there. But once I pulled it out of the sidewall, it was obviously bad. Terminal completely corroded through. Everything downstream from there inside the RV was dead. And that patio outlet was the 2nd item on the branch.
Then once I had a junction box open. And it was inside a wall. No way to get to it without major remodeling. So I bypassed it, left it alone since it's main branch was working normally. Used the MicroWave 20 amp circuit to power the dead branch by extending it and back feeding the bad branch. Still took some remodeling work, but much simpler than tearing out a wall.
I'd recommend you either get that drawing from CC, or make your own, using the CBs as telltales so you can chase down the exact branch that's opened.