It will probably not be insurable, except for the liability coverage. Good Sam is nothing but a broker for the actual insurance company and has no say in what that company will, or will not, insure. You may find a multi-lines insurance broker that can arrange for "stated Value" coverage on the RV. It will be much more expensive than normal comp and collision coverage. Hopefully, you got a very significant discount from what a non branded title trailer would have cost. If you did, the savings should more than offset the increased cost/unavailability of comprehensive coverage.