With a 5 year old and a 7 year old, you may enjoy spending a half-day at Disney's Fort Wilderness Campground. Can't go swimming at resorts where you are not a paying guest but you can wander and explore. At FWC, park in the lot next to the lobby, go in and request a resort map, take the internal Disney bus to the Meadows or better yet, all the way back to the marina area and beach. You can get off the bus at any time, whenever you see a playground to try. There are also basketball courts, tetherball and other game courts scattered through the campground - often with a ball there or nearby. The beach area used to have hammocks - don't know if they still do. At the stables near the marina area, there are usually horses that the kids may pet. There's also a nice nature trail near the lake.
Back at FWC's Meadows Trading Post, you may rent bikes and canoes for the canals. If you're there in the early evening, Chip N Dale come by for a short singalong by a campfire pit and it's followed by an outdoor Disney movie. Nice to have a blanket to set out and sit on, or there are a few benches.
Other Disney resorts, hotels are worth a visit too. You may get a free 3 hour parking pass to visit nearly any of them and look around:
Disney's Caribbean Beach Resort has a fun playground, lakeside hammocks and sandy beach for playing. Port Orleans Riverside has an exceptional "fort-style" playground. Then take the Disney friendship boat down the river to Downtown Disney and boat or bus back later. Returning, you may decide to get off the boat at Port Orleans French Quarter, explore a little and walk back to POR along the riverside paths. All three of these moderates offer food courts for a modestly priced meal.
If you've never seen the Wilderness Lodge, with it's beautiful lobby and fireplaces, check it out! Stop by Concierge Services and ask for a Hidden Mickeys list. Then go on a "scavenger hunt" for Hidden Mickeys in the resort to find them all from the list. Time your visit to include watching for the outdoor geyser to go off, roughly on the hour every hour.
You don't have to be a Disney Resort guest to park at Grand Floridian and take the monorail around to the 3 monorail resorts, collecting pressed pennies from the machines in their lobbies. The tiki torch lit walkpaths at the Poly are especially pretty at night. If you do this later in the evening, choose a resort on Seven Seas Lagoon (GF, Poly, CR) or on Bay Lake (WL, FWC) and watch the nightly Electrical Water Pageant from the beach as it goes past.
If the kids love to see animals, visit Animal Kingdom Lodge, park and walk through the lobby, out to the animal viewing areas.
Don't do any of these visits midday when it's very hot out. Seeing other children swimming in the fun resort pools may be a bit hard on children who are not allowed to join them. If it's cooler out, they probably won't notice as much. And you can steer them in other directions away from themed pools.
If your family likes state parks, look at their website and see if any appeal to your interests.
http://www.floridastateparks.org/ Several in central Florida have picnic areas with great walking or biking trails, some with canoe rentals and swimming too. Blue Spring State Park has lots of manatees when it's coldest in winter, usually before Christmas until at least February, sometimes later. It's beautiful year-round with shady boardwalk trails along the water's edge of the springs... lots of trees dripping with Spanish moss, so pretty. Other state parks are out at the beaches on both coasts, just 1-1.5 hours away if you'll have a car and they have good pavilions at many with showers, food concessions, etc.
If you already have a museum, zoo or aquarium annual pass, check out the Orlando Science Center, where you may get free or deeply discounted reciprocal admissions. Quality museum here! Great hands-on stuff for kids and exhibits with live young alligators and other indigenous animals. Our kids loved this place when they were just a year or two older than yours.
If you want to visit the other area theme parks, look for a discount on a one-day ticket to Sea World (
AAA?). Inside the park, you can go to Guest Services and get a certificate good for a 2nd day free (everyone signs these there), return within 7 days. You just have to pay for parking the second day.
Universal's CityWalk has lots to look at, window shopping, restaurants and a movie theater - and parking in the parking garage is free after 6 pm nightly. Very nice if you want to walk through CityWalk, get on one of the boats and visit any of the three, themed resorts there. They're also connected by nicely lit and landscaped walkpaths. Interesting and quite different from Disney's.
The Universal theme parks often have great special webdeals for advance purchase of a 7-day park pass for ~$100/person with parking hopping between their two parks. So reasonable! And yes, there's stuff for your young children there! Love it!
Hope this helped!
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. Green Tomatoes (or something named like that at the top of Int Drive also gets good reviews) 
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