The GFCI breaker with a reset button was in a small receptacle next to sink in 2003 TT bathroom and after I looked at the wiring and pushed them back into the tiny outlet this placed pressure on one or more of the wires and when I plugged into shore power they popped again. Everything worked fine if I left the wires dangling outside the outlet and close to sink. There may have been another GFCI outlet in the kitchen cabinet area but do not remember after 5 or 6 years. TT was sold at good price to Reno RV dealer for use at Burning Man festival and I let him deal with the issues.
Trailer was an R Vision Trail Cruiser bunkhouse model