Windsor Hills has its own water park/pool complex, playgrounds, game room, etc. There's PLENTY to do there on a resort day, even with your little ones. When we're staying offsite near WDW with littles, we sometimes enjoy a non-park day on Disney property doing lots of things:
Park at Disney Springs, ride a boat from Marketplace dock up to POFQ for beignets, walk to POR's playground, and ride back. Before leaving DS, the littles like a ride on a tiny train loop and a small carousel (token$). When they're older, we'll probably switch to the tethered balloon.
Park at TTC (using an AP for free parking), ride the monorail to MK, boat to WL to explore the lodge and hunt for hidden Mickeys (get list of clues from front desk) or boat to FWC to visit the horse barn, take a pony ride, and play on one of the playgrounds.
Park at DHS (using an AP for free parking), ride the Skyliner (our grandkids' favorite) to Pop/AoA to have character or Mickey waffles, play on AoA's mini-playground, and ride back. If it's near lunchtime, we may visit Riviera's Primo Piatto for a meal, instead of Pop/AoA.
The
WDW Resort Playgrounds webpage lists which of their resorts have playgrounds. Note that the Swan/Dolphin's playground is in a sandlot, not far from the Boardwalk. None of them are particularly large or exceptional but all offer a chance for the littles to play when adults want to explore a resort.