You will find high-volume discount RV dealers in the Elkhart area who specialize in out of state business, different dealers for different brands. Not all are in Indiana, some are in southwestern Michigan. Similarly in northern Iowa for the brands built there, eastern Kansas for the brands built in that area. These I know about, but I would expect a similar situation for RVs built in Texas, California, and the Pacific Northwest (which includes Canadian exports).
Finding these dealers? Ask the sales department at each particular RV manufacturer. Jayco has told me where to look for models not in the showroom, Winnebago makes similar recommendations for a Forest City dealership.
So the idea, in principle, is buying close to the factory (it is not always in Indiana) saves transportation costs, and buying from a high volume discount dealer who turns over inventory quickly often gets you a better discount.