We will often schedule a character meal for the "off days". Last time we went to WDW, we stayed off site. One day was dedicated to "Disney" that wasn't in any of the parks. We went to character breakfast at the Contemporary (Chef Mickey's, right?), then went over to DtD and wandered around, bought some souvies, had a late lunch. The kids played in
lego land. We had an ice cream. Had they been bigger (and we'll probably face it for the next trip) they could have gone on the little boats there. I believe you can take the boats to the resorts (a free boat ride) from DtD whether you're a resort guest or not, but don't quote me on it. At night, from the Contemporary, I know, and I believe from the Poly and Grand Floridian, you can watch the water electrical parade. There are evening cruises that you can go on (the last time I went Decades ago it left from the contemporary) and see the lights and usually the fireworks over MK and then the electrical water parade.
There's wet and wild or any of the Disney water parks that you can do on non-park days. Maybe Disney Quest? Sea World is probably my favorite non-Disney park.
Also, stay at a place where you like the pool (go over to the Orlando board, they would have a bunch of help) and spend a day playing at the pool, going out to dinner, etc. Then maybe you could spring for the Mideval times dinner show or something.
Doing a variety of things, you should be able to fit in shopping there somewhere!
Oddly enough, looking at Orlando area stuff, and the boys really want to go to GatorLand! Ewwww.....but, could be a good split up activity....you at the outlet, maybe with DD and Dsis, and the 'boys' going to gatorland!