I would not use them. Your on CL & RV trader, I think that is all you need.
Just my opinion, but if I were selling a big toy hauler like that, I would probably go the consignment route. You may have to pay an upfront fee for them to do their PDI inspection to see make sure everything works. They may want a commission.
A friend has a Cyclone on consignment. He paid $1,200 up front and that's it. No commission, etc if/when it sells. The benefit to this is potential buyers can shop and get financing at the same place.
Another dealership I know will charge $400 upfront, then 10% commission at the sale.
If you have it on CL and RV Trader, it's not a bad idea to market it that way, yourself. (I'd say theres a 50/50 chance your buyer will find it using RV trader or CL). The of 50% is a buyer passing by an RV dealer.
Unfortunately camper values drop pretty hard/fast. If your rig is not selling, it's almost always a price issue. Used rv buyers are either RV knowledgeable are looking for a specific floor plan/vintage camper; and/or they want a big savings.
The higher value of camper it is, the bigger discount/loss you are most likely to get.
2016 Road Warrior 355
2015 Ram 3500 Cummins SRW 4x4 MegaCab ShortBed
2011 F150 ecoboost - Traded
2015 Jayflight 28 BHBE (sold)
2009 Jayflight 26 BH (sold)