1. You just joined. You need to post Year/Brand/Model and mileage of the Motorhome to get any real help about cost
2. EPDM(Rubber) roof's are NEVER--NEVER partially repaired. The complete roof and under decking has to be replaced. Reputable Insurance companies pay for that. Average cost JUST for the roof repair will be in the $6000 to $8000 range at average $150 labor rates
3. To the other poster, Insurance adjusters do not get spiffs for reducing payouts. Now, Independent adjusters YOU hire to get a more fair settlement from the insurance company on a claim may charge a percentage of the extra money they get you.
4. Since you state the Insurance wants to pay for partial, I will bet it is Geico or Progressive as they are the biggest pains to deal with on RV claims.
5. Your other high cost item will be the front area where the dash/TV is. Since the wood has rotted, rebuilding that front cap area will be a nightmare in cost. Odds are the front cap will have to be pulled to do the job correctly.
Doug