What a dealership will offer you will be NADA resale for the bike, less the profit amount they want to make if they put it back on their floor to sell. There isn't much value to the add on's for trade in's, only a private buyer will give you that additional value. NADA resale is the max amount a bank will loan on the bike - and that is what they make their decisions off of.
If the dealership wholesales the bike out right away vs. turning it on their own used bike floor, that offer will be significantly less (black book value) than the NADA resale. The dealership knows that you save sales tax, the hassle of selling, and the incurred cost of selling (Ebay isn't free). You should put it on Craigslist, accept only cash offers, and you may get a buyer. Spring Time is in the air, and bike sales will be picking up.
Also remember the dealership wants to make money on both ends. The overhead for a HD dealership has everyone getting paid commission some where. If a dealership offers you more than the NADA resale, they are taking money away from the profit built into the new bike sale. They will move virtual money around to make a sale, and maximize profit for the dealership. You can always negotiate discounts on add-ons, warranty, and gear at the time of sale too.
If you saw the spreadsheet I was toting around when buying my 2012, I could put in all those intangibles to negotiate the best deal for me. One of the sales guys took a look at it and shook his head, I think I heard him mutter f'n engineers to the sales manager. I also spent 20+ years in hi-tech sales, which does give me an edge in negotiations because I do my home work going in, and am willing to walk away.
Bottom line, the dealership will make money. Bottom line - your going to love your new ride. Buyers remorse will only last as long as it takes to get your new bike on the road, then the grins will begin!!!!