I have replaced some of my copper in the house with Pex & sharkbite fittings. The big problem I had was I was not pushing the pipe into the sharkbite far enough.
When I 1st pressurized the system ALL my sharkbites where dripping! I realized my mistake, shut off the water & reseated the sharkbites. Repressurized and no leaks. I was easily able to use the sharkbites to transition from copper to pex.
If I were going to install PEX in my MH I'd look for the straight sections of pex. When I installed PEX in the house the pipe is coiled up & getting the pipe straightened out is a real P.I.T.A.