Best way of getting a discount on a custom order?

I plan on ordering my RHO soon. That said all of the dealerships near me have RHOs for MSRP or like 1k off which is nothing. I know I can order through Mark Dodge and get the best discount possible but I live very far away from them (metrowest MA) and it would be hard to coordinate a trade and taking delivery. How do I get my dealerships to actually discount the truck. (Obviously I negotiate but like how)