We had a 2000 Triple E Regency and I know the GFI is located in the bathroom.
The GFI would pop periodically, but I just never got around to replacing it.
If you have the Regency XL on the E450 Chassis v-10, in my opinion, you have one of the best Class C's on the market, even after 17 years!
Keep it serviced and detailed (waxed) annually it will keep it's stylish look and compete with any other "C" on the market today.