Been doing this "RV" thing since 2002 on my own and with my folks since I was a baby.. Have yet to need any service to bail us out... Just lucky I guess..
I've had my grey tank literally fall out on me.. Twice.. But they happened while in camp and I had the tools on hand to fix it on the spot, as it was just the brackets that held the tank up had shifted. Easy fix for the most part. I've had other little things happen, but always seemed to be able to fix to the point of at least getting to the intended destination and dealing with it there. So far, nothing that has ruined a trip.. Just made for a good story later on! :)
I probably pack an extra #200 of tools and other stuff for the "just in case" stuff that happens. I hope to never need or use it, but I pack it all the same. I've loaned out tools to others in camp and have had other supplies on hand that has helped a fellow RVer out in a pinch.. Good Karma might be on my side too? ;)
My plan B is the multiple CC's in my wallet.... :)
Good luck!
Mitch