Irecently replumbed my Motorhome.
Had I planned the work better I wouuld have just done it all at one time rather than in phases and stages as I shifted from the bathroom to the kitchen to the supply system etc.
say la vee
As to pex the key is working on the "assemblies" away from their install cubby holes and then installing all put together manifolds.
Apollo makes a tool to remove the old copper compressio ring ( save 3 fittings and it pays for itself). The mini crimper tool is a PITA. It works but man oh man. Much better to plan the job and rent/borrow a long handled ring crimper tool.
When I get my head above water I'll post up some pics.