First question is do you have a trade-in? Even a "sale price" or "show price" can probably come down a little more on a clean deal vs a trade in.
You are pretty close to the big internet dealers - get a price from RV Direct or RV Wholesalers, or somebody like that. That should give you a good reference point. Then you can try negotiating from there.
Never heard of mfg discount for a show, but maybe... Generally you can get a show price after the show. If they can sell it for XX at a show and make money, they can sell it for XX off their lot and make money.
2005 F-150 FX4
2013 Rockwood Roo 23 IKSS