At most of the shows I've attended, 20+ various places around the country over a dozen years, show prices have not been very different from the prices the same dealers have back at the lot. For really big shows that permit on-site sales, like the Tampa Supershow in January, some manufacturers will send extra stock directly to the show with a sales incentive that might adjust the price slightly downward.
Another source of price breaks at shows will be the lot queens, stock that the dealer has had for a year or more and just has not been able to sell it off the lot. These get brought to shows for exposure to potential customers who would never visit the dealer, and prices are often marked way down so that the dealer has a better chance of not hauling the thing back to sit on his lot.
I find shows useful to see what is out there, but not always useful for gathering information or buying. Factory sales representatives, or regional sales managers, will often show up and work with a dealer; these folks are good for product information, but not for making a deal, they have to find you a salesman working for the dealer. At larger shows the dealers will hire temporary sales people, who might otherwise be selling cars, home warranties, replacement windows or suits. Most cannot be very helpful, and some might be honest enough to tell you that they don't usually sell RVs. If you want to negotiate with them, they usually have to go to the dealer's sales manager for authority.
If you buy at a show, chances are pretty good that you won't be taking the RV away from the show, it will go back to the dealer for pre-delivery prep. Most buyers are not prepared to take the RV away anyway, particularly towables. When a RV is bought at a show, it might be closed up, or it might be left open for more people to look at, because the dealer has more of these to sell back at the dealership. If you buy a $1,500,000 motorcoach, chances are it will get a "sold" tag and locked up. If you buy a $12,000 travel trailer, chances are it will remain open to the end of the show as a model for more sales.
Weight distributing hitch is something you buy separately from either the hitch receiver (if you don't already have one) and your other towing equipment (like trailer brake controller and electrical connections). Dealers will often put together a package deal for the trailer and whatever additional equipment you need for towing. This package usually includes equipment installation and first-time setup of the hitch, which takes some expertise, and teaching you how to do it.
