You can do much better selling yours outright, but it's mostly a matter of luck finding a buyer. Once in awhile RVs sell quickly, but more often than not they hang around quite awhile waiting for someone to fall in love with it. I know people who have had rigs on the market for a year or more, even with a price set below book value. So try selling on your own, but don't be disappointed if it doesn't sell quickly.
A dealer is only going to give you low wholesale for your trailer, regardless of condition and options. Anything else you get is a discount on the selling price that you could have gotten anyway, e.g. with no trade-in. And there is no need to wait for a show - the discounts offered at most shows are trivial anyway - usually only 5-10%. You can get 20% off MSRP if you bargain HARD. Don't be bashfull - walk out the door if they don't want to deal at your price. There are many other dealers for the same make & model.