Maybe you could pit the far dealer price against the local dealer and get them to lower the price.
I'd send the price info on your best price in an E mail to each dealer. Tell them you have money in hand and want to finalize the sale within a few days (if that meets your schedule). I'd bet you would get a similar offer.
Otherwise, if you're not one of those folk who have to bring the trailer back in for warranty work every time a screw gets loose or pipe fittings leak, travel the 6 hrs to save the money. I know that's what I'd do if buying new.