Potential breakdowns are just part of the experience of RV travel. A road service plan is always a contingency that gives many a sense of comfort and works well in most cases.
We just completed a trip from PA to CA and back, just under 6,000 miles and had a major problem with the exhaust system. The pipe exiting the turbo broke off and was dumping exhaust under the bed and required some serious repairs with parts that are just not normal in most exhaust systems today. Just smaller size than common use today, so we ended up stuck for the weekend in Ogollala, NE.
We were fortunate to find a good shop (suggested by another shop who did not want to do the repairs) who did an outstanding job under the circumstances and had us back on the road Monday afternoon after a Friday afternoon arrival at their shop and an extensive search for parts on Friday afternoon. Would we have liked to be fixed and back on the road Friday afternoon? Certainly, but that wasn't reality and we were within a mile or so of a very acceptable campground and were able to drive the coach there and back so we were inconvenienced minimally and worked out the problems.
Long story, but I would recommend Big Mac Diesel in Ogollala, NE completely. They don't look like much when you pull into their lot and don't have any fancy waiting room, but they are very competent and did a difficult job for us at a very fair price.