Is it possible to tee into the water line right before the water heater and another tee tight after the water heater line. Then run PEX type tubing any where you want or can? Then you will have hot and cold. If all you want is cold, then just put a Y adapter at the campground spigot and run another garden hose with a sprayer end.
I saw one modification someone made by tapping into the lines before and after the water heater then drilled holes through the floor, and the pipe came out on the side of the camper, but under the floor level. It also aided him in draining his system for winterizing. Something to consider.
