Unfortunately, the marina is not particularly close to the lobby area at the resort. Because of the resort configuration, IMO, there is no great spot for the marina. It's present location is out of the way of the boats on the lake and is protected in it's Trumbo Canal area. If it were placed near the Fireworks Pavillion, it would require lots of foot traffic thru parking lots and grounds of Buildings 2 and 3. In it's present spot it seems to be a similar distance from Buildings 1-4, 5,6 and the lobby. Buildings 8-12 will have a bit further distance to travel (maybe 200 yards farther).
For most buildings (3,4,7-12) it will be about the same distance to walk to DD as to walk to the marina.
Enjoy!