I wouldn't worry about the RV end of the equation, that won't leave you stranded.
25yrs at GM store serv departments....what do I know?
Are you dealing with a GM Store?
The best option is always go with the plan supported by the manufacturer.
If your vehicle is still covered by a General Motors Protection Plan.(GMPP), you may be able to extend the policy.
One of the best to deal with was Interstate
Another one Hertz.1-800-654-4171
I've been retired too long to offer any more....Get some names and I'll ck my phone files.
Be careful there are a LOT of FBN outfits, that ain't worth a hoot.
I just did the google on them