When we we're looking at the Newmar's the dealers gave us a build sheet from the factory with the prices all on it. Check with a couple of different dealers to make sure you get the right one. Build your coach according to the sheets.
I would suggest holding out for close to 30% discount, as a factory order is a guaranteed sale, and they have no floorplan costs. Do not hesitate to let them know you shopping it around.
A factory order puts you in control, cause you can order from anyone.
Also when you get them to quote you make sure it is an out the door price, with no add ons in price.
Also ensure that they include a full tank of fuel and propane if applicable.