The first time we were actually stranded by a break down was a starter failure. We got the truck into Lexington Truck Sales. Could not get a new starter until the next day, The dealer let me use a yard mule to move the fiver near the building where we could plug in and we spent the night in the dealer's yard.
Another time we had a broken spring on the fiver and it took several days just to figure out the correct parts needed. Spent a week in an RV Park in Huntington, VA. that time.
Pretty easy to adapt when you have your house with you. Sometimes one has to spend extra time waiting out the weather. Granted flexibility is tougher when you are vacation traveling with limited time, but you do your best.
The important thing is to relax and enjoy yourself, get a good road service policy and worry about solving the problems if and when they occur.