What's the make/model of the trailer? not all 23/24 ft trailers are the same as there are many types of travel trailers.
I can't remember if the Expeditions are still limited to 900 lbs of tongue weight, but that could limit you to a trailer as low as 5300 lbs loaded once you factor in a 100 lbs hitch system. This was something I was concerned with when looking at older expeditions as mine would be slightly over.
How old of an Expedition are you looking at? Are you looking at a regular or extended length? Have you considered Suburbans too? Will this be a daily driver or dedicated tow vehicle?