1363 will be your max payload which is your tongue weight PLUS the weight of people and cargo in your tow vehicle. The Nash 25c is listed as having a dry (empty) tongue or hitch weight of 555 pounds. So if you load the trailer up to capacity you might be looking at 700-800 pounds of tongue weight. That leaves you with maybe 560 pounds of payload in the tow vehicle which would quickly be taken up if you add in the weight of four people. Basically the Nash will be a full load for your Expedition but possibly doable if you set it up right.
