Originally Posted by ourflat
water started pouring out my fresh water tank filling nozzle.
I'm betting you have debris in the check valve at the 12 volt on-board water pump. When you connected your water hose at the campsite water back filled into the fresh water tank via the check valve.
The propane regulator its a common failure. Unfortunately it happens at an inconvenient time and most costly opportunity; loss of a full tank of propane and you are 100 miles from a decent RV supplier so you have to buy one from a camp store at 3X the normal price.