Simply put, your coach battery died. I'll bet the tripped breaker was the converter. It takes 120 volts AC and converts it to about 12.5 volts DC which charges the coach battery and supplies 12 VDC to the lights, fridge control, etc.
Now I have no idea why it tripped. You might have to think back to what might have been going on before the lights started to dim.
2000 Cherokee 29BH with 6V batteries, LED lights & 400 watts of solar power, flipped axles and raised. 2007 Tundra 5.7L DC-LB with lots of mods. C-co, 8/158th AVN Maint.