Plumbing Repair Kit to Carry With you. Just in Case...

I carry one of these and stainless steel wire
http://www.clamptitetools.net/

I do have some PEX tubing and sharkbite fittngs leftover from a recent plumbing add on I completed. So those are now in my goodies box in the compartment where I store all of the tools and other fix it stuff.

Like others have said most of the time I have to run to the hardware store for correct parts or mickey mouse (here's where the ClampTite Tool helps) something to get by until we reach civilization.