You're just asking for trouble and/or disappointment if you try to involve a repair shop from a whole other industry. It might be the same materials but it's not the same construction techniques.
Ideally you want the manufacturer to fix it. You're already two degrees separated by trying to get Camping World to handle the fix. They don't sell the units and while they *should* be able to make the repair, there's always "reasonable doubt" and if the repair fails, both parties will have plausible deniability. EC will say CW did the repair incorrectly. CW will say EC gave them bad information for repairing the camper.