On my previous trailer I had problems removing the caps. I replaced with brass valves from HD. Took the handles off so no one opened them on me when I didn't want them to be open. I stored the handles win my water connection bin.
For the PEX tubing I bought a crimper and clamps since normal hose clamps don't work on those. Another tool & clamps I keep in my onboard tool box. Came in handy when I had a leak under the bathroom sink while traveling.