Troubleshooting a leak

[LNBright]

Our first trip of the season was last week, and while preparing for departure, discovered a leak. Didn't let it ruin the trip, still had a good time... But... Now that we're back, I need to repair. But before I start tearing things apart to get to it, I want to understand what it is I should be expecting, how to go about getting to it, etc.


So, camper is a 20FB: end of season last fall, winterizing, I'd drained the tanks (black, gray, fresh, and water heater), opened the drain valves, put my air-adapter onto the city water connection and used my air compressor to ensure both the sinks, the shower, and the outdoor shower, were blown out, then, I turned on the pump bypass and put a gallon of RV antifreeze into the lines (ensuring it came out both sinks, shower, toilet, outdoor shower), and put plenty into the drain lines.

So in dewinterizing, I'd closed the drains, filled the freshwater tank. Then, when I put the water hose onto the city water inlet to begin flushing the antifreeze out, I immediately have water start running out from that back corner, below the shower, above/behind the tank dump station. Thus my first thought was, perhaps the water pressure regulator had gone bad, and the water was thus getting into between the inner and outer wall there, running out the bottom. But, the water inlet is forward of the toilet, whereas when inside the camper, it sounded like it was behind the shower wall, towards the rear from the toilet instead (which, is about where the water was coming out).

With the city water off and disconnected, there was just a slight drip: if we left the pump switch on, maybe every other hour or so, the pump would kick on for a second to repressurize, whereas it normally doesn't do that, and there would be an occasional drip from that back corner, keeping a damp spot under the camper while parked.

I haven't yet swapped out the inlet/ pressure regulator, which I still suspect, but, I wonder what else might be having a leak to have the (very) intermittent drip. I will admit, I'm not looking forward to trying to remove the shower, especially if it doesn't really need to come out, but I'm not sure how to proceed to see what might be leaking behind there without it coming out.

Comments, suggestions, ideas, open to such....