Lowes also carries a line of no-clamp PEX fittings, WATTS WaterPEX
. It's easy to use, just be careful to install it in places where the fitting won't get flexed by trailer motion or bend, and make sure you cut your pipe with square ends that almost meet in the middle before the pipes are inserted into the fittings. I also secure the pipe leading to the connectors and secure the connector in place as well.
Here's a pic of one of these no-clamp fittings connecting my cold water line to my water pump and city water inlet. You can see how the pipe and the fittings are all clamped firmly to the hot water line using zip-ties