What do you call walking distance? On site it's 15-20 minutes, Cheyenne or Santa Fe.
Off site, also about 15-20 minutes for Hipark by Adagio Serris in Val d'Europe, there are more hotels in this area, Hipark is the closest, but not the cheapest.
Best to have a look at sites like Expedia, booking.com etc. and see what matches your budget. Also check which hotels offer shuttles to the park.