I highly doubt that you'll find anything near the resort itself, as it is out in the middle of farmland with little development nearby. That said, it is a simple train or bus ride over to the park from Paris, so you're best bet would be to stay in Paris and just hike it over the day of travel. It takes around 45 minutes to get there by RER.
Yeah, for a hostel it's probably best to stay in Paris and get the train out each day... although you can get pretty cheap deals staying in the hotels in the town nearby (Val d'Europe, if my memory serves me right!) and free busses run from there throughout the day and evening.