Closest resorts are the Epcot Resorts, specifically Swan, Dolphin, Boardwalk, Yacht & Beach club. Swan is technically the closest (as the crow flys) but all 5
resorts are walking distance (20 - 25 minutes) to MGM and offer boat service as well. If you like walking and the weather is favorable, then the walk is fine.
For the adventurous few, you can also walk from CBR (we've done it). Exit across the lawn by Aruba, across the street via the crosswalk to the firestation.
About a 10 minute walk to the Hess Station, across the road (ecpot resorts blvd. I believe) and down the path, under the bridge and voila. Probably 25 - 30 minutes start to finish