I'm 71, and motorhome breakdowns are just something I deal with when they occur. They're not something I worry about in advance beyond having a good emergency road service plan. Over the years with various RV's, I've had a blown engine, a blown transmission, and a blown rear end assembly, all of which required major repairs when we were nowhere near anyplace where we knew anyone or any repair shops. Our road service has always found quality shops for us that were able to make the repairs as quickly and cost effectively as practical. Sure, we lost as much as two weeks of our trip, but since we're seldom on a planned schedule anyway, that didn't matter much. Of course, we've had other more minor issues along the way, but again, we just dealt with them as needed, either on the spot or when we were settled in for a bit somewhere, depending on the issue.
As I see it, worrying about what might happen is a waste of energy, since there's no way to plan for all contingencies anyway. Do your preventative maintenance on schedule and enjoy your RV as it was meant to be enjoyed!