Ah, the long run dilemma, I know it well. I haven't run at the MK resort area other then the half marathon but I see no reason why your husband can't use the surrounding roads. I have walked the road that goes from the Poly to GF so I see no reason why he couldn't run it. I would check out the bird's eye view of Bing Maps to plan a course. It give you more perspective than aerial.
If you have a car or he is willing to travel I would highly recommend him going over to the boardwalk area for a run. I love to go around the Crescent Lake and down the canal towards DHS. It isn't a long run (.8 around the lake + .875 down the canal for a total of 1.675) but it can either be run twice or as part of a longer run that incorporates the longer routes you can find
here.
Another run I like is up and down the river at
Port Orleans. You'll have to do a couple of laps to get in a medium run or a lot for a long run but it is beautiful. I am not sure if he wants to go travel around to run but if time permits it is a great way to get in some unique runs.
Have a good trip.