If your concern is only breakdown insurance then perhaps you should look at extended warranty products. Many will pay for some degree of trip interruption, or there is just trip interruption insurance. But really, if you have a toad or a tow vehicle you probably will not need to rent a car, and I don't know of anyone who will rent a replacement RV. Hotel/motel expenses in the boonies and food reimbursement may not be justified vs the cost of the policy.
You might try calling Wholesale Warranties and see what products they offer but I bet your looking for something that may not exist.
