It really depends on your pace, and your family's comfort level with traveling around property. Each year runDisney will put out a spectator guide, which will provide estimated travel times and easiest ways to get from A to B. And based on your runners pace, they will tell you what places you should be able to get to. If they are using Disney transit your options are really only going to be the Start, TTC/MK area, and Finish. For the first few hours of the race, the only transit running will be the monorails from Epcot to TTC and then the MK resort loop. At the TTC/MK area depending on your runners speed you may be able to see them at the TTC, and then get over to the GF/Shade of Green area and see them pass there as well. If they watch from Main Street, you very well may not have enough time to get to any other area. (Possibly get to GF, but that may be tough) Keep in mind that at most of the popular places to cheer from, there may be 4-5 people deep at the fence, and it may take a bit to make their way to the point where they can see. Lots of people will also watch from the Boardwalk/Beach/Yacht club area, but if they cheer from there, they won't be able to make it to the finish in time. It all depends on what they want to see.