I replumbed all the supply lines on my 68 with PEX.
So far, I am happy with it. I used the crimp
fittings. They are not as forgiving of mistakes (you
have to cut them out). Their variable cost is much
less expensive than the tubing-style fittings (the
compression fittings you tighten with a wrench). Of
course, you have the fixed cost for the crimp tool,
which is about $100. Get the short-handled one
because it is easier to use in tight spaces. If you
choose to use the tubing/compression fittings, read
the fine print. The Quest brand says they are not for
use behind closed walls! Who knows why. Maybe
they're prone to leaking over time.
I chose to plumb my lines with red and blue PEX, so it
is really easy to tell hot from cold...
Jon in SC
68 Overlander