I'd suggest that you simply use campground water to fill your tank, but then turn off (or disconnect) the hose and use only your onboard pump. 1. You never have to worry about the pressure being too high. 2. If there is a leak somewhere in your system, you will be alerted to it by the sound of your pump cycling.
We don't stop playing because we grow old...We grow old because we stop playing!
2004 Itasca Sunrise M-30W
Carson enclosed ATV Trailer
-'85 ATC250R, '12 Husky TE310, '20 CanAm X3 X rs Turbo RR
Zieman Jetski Trailer
-'96 GTi, '96 Waveblaster II