Well, we just got back from our trip. We went to MGM in the morning and took the boat to Epcot in the afternoon. Our plan was to head back to MGM for the 7PM Illuminations show. Also had the car parked there. The last boat was at 7:30. We were running late at Epcot and there was no way we would make it back for the show. Dh asked a service member how long it would take to walk to MGM. He was told 10 minute. I know the boat ride was 25 min. but thought maybe there was a walk way or something. Anyways, we ended up staying to watch the show at Epcot and took the boat to the Boardwalk around 9:30. We figured we would walk from the Boardwalk to MGM. The boat driver was very nice and offered to drive us back to MGM since it was late and we had 4 kids. So to answer your question, it will take at least 30 minutes to walk depending if you have young children or not.