We've got a Marriott time share 5 mins from Disney, and go twice a year. Kids happy but we need 'excursions' to keep sane (-ish)
Decent sights nearby (i.e. not manufatured Disney), but rely on car:
1. Meaux - an old town just east of Disney on the A4 motorway (but you have to pay a toll).
2. Local restaurants. There are 3 in the small village of Villeneuve le Comte (10 mins south-east-ish of Disney), all delightful typically French, good food, good value. The village looks typically sleepy French, you might have to book a table. One's called La Prune, one's called Au Bonne Marmite (or something like that), can't remember the third. All highly recommended
3. The big shopping centre at Marne-La-Vallee has a (good) Sea Life centre, an Outlet Village (saw my first Maybach there) and a massive Auchan supermarket, whose prices confirm that rip-off Britain is well and truly alive. If you're driving you can stock up on wine in comfort without being surrounded by hordes of lager-louts, like you get at the ferry ports.
4. Of course further afield there is a little place called Paris, as well as the Champagne region.
For eating in the Disney park, I reckon the best is the Lucky Nugget, a Western style self-serve with live music (lunch only I think). There are loads more restaurants and cinema at the Disney Village next to the Park, open to all.
In Disney Studios, be sure to see the Action Moteurs Stunt Driving show.
Have fun!