Barney,

Based on the pictures, it appears there was a failure at the crimp or a loose connection. If you have an IR heat gun, and you should, I'd recommend you put a high current load on the coach, at least 40A on each leg, and keep the load for at least 15 minutes. You can set the air conditioners at their lowest setting so they don't cycle and turn on the hot water so the hot water heater will stay on. After 15 minutes of high load check each connection (screw and crimp) as well as the relay contacts. You will be looking for any reading that's higher than another on L1 and L2 connections and relay contacts. There will be no current going through the generator relay and near zero through the neutral, so expect these to be much cooler.

I'm glad it was just some wire. It could have been so much worse.

While you're at it pop the circuit breaker covers in the bedroom and next to the transfer switch and make sure all connections are tight, especially the mains.