It seems to me that if you try to avoid issues by proper PM and pre-trip inspections, carry appropriate stuff for the most likely problems like tools, extra fuel filters, a serviceable spare, jack/cribbing, etc. and knowledge that comes with experience and TM reading, most issues are manageable. Having a network of buddies, even if they are not into MVs is helpful. Paying it forward helps in this regard.
Then of course is the possible help from folks on this site. It may come in the form of a phone number to call for advice on how to resolve your problem. Or it could be someone on their way as soon as they can. Understandably, this could require patience.
Lastly is to have a fair amount of $$$ available, if it comes to that. Take what you would pay in premiums to a company for roadside assistance and squirrel it away for this purpose.
I have extra trucks and a tow bar, for just such a case.