I've made a couple trips to Orlando w/o going into the WDW parks. It's tough because you can almost touch the parks, but you can still have fun.
- Ride the bus to some of the park entrances. The MK entrance isn't too exciting, but the Epcot entrance has a gift shop plus the monorail. The MGM Entrance has a small gift shop plus great views of the tower. AK's entrance has a cool gift shop, plus the Rainforest Cafe
- Take the monorail to Epcot. You can kind of experience some of the park since the monorail cruises right over Future World
- If you can get to the International Gateway area, you can see some of Illuminations without even going into Epcot (I think the bridge that goes over the water would be a great place to watch from)
- Take a boat cruise from Downtown Disney to both Port Orleans resorts. The French Quarter is the easier of the two to explore, but the main area of Dixie Landings is more fun (the food court there is better, and the main island is fun to explore)
- Play mini golf at Fantasia Gardens
- Watch the Electrical Water Pageant from the beach of the Poly. Not only is the resort gorgeous at night, but that's the best place to watch it from.
- Resorts, Downtown Disney (you knew that)
Even though you can't go into the parks, there is still a lot you can do to experience some of the magic.