I can maybe answer a few of your questions.
This will be our fourth year attending and third time camping there. Best way to see the show is to stay over night either camping or the other way. If you are shopping you might even need more than one day, the show is that big. The weekend it's packed. If you can get there Thursday the crowd maybe a bit less.
Our first year, 2010, was at a hotel in Harrisburg. Second year, 2011, was with the coach with reservations at Hershey High Meadow CG just down the road. Problem was they were flooded the week prior and had to cancel ALL reservations. Ended up in the back end of Elizabethtown KOA. The site wasn't exactly to my liking but is was a week before the show. Last year we stayed at Gifford Pinchot SP which was great. This year we're going a bit further north Little Buffalo SP.
Last year and the first year we attempted to drive to the show on US 322 east out of Harrisburg. 10 mile long parking lot. Coming up out of Elizabethtown into the back side was pretty smooth. This year we're going to see how the traffic is coming in from the north. Note to self, go easy on the morning coffee. You can boondock at the show. Details can be found
HERE.
Not sure about deals. The factory sales reps will be on site but you will be negotiating with a local (Mid-Atlantic) dealer. At least that was my impression.
2006 Hurricane 31D built on a 2006 Ford F53