Echoing....
First, just want to make sure that you do know - No walking to the start from the Beach Club. Sadly, every year a runner will not realize and end up having to scramble for the start.
Busing or driving works equally well. I would say that if you have a car, the 5k sets itself up as a race easy to drive to as there are no road closures to deal with. For the half, should you decide to drive, make a Left out of the BC parking and drive by the Swan and Dolphin. Then right on Buena Vista and right onto World. The other route (going by CBR is closed off for the start).
Either way, plan on leaving your resort in the 0330 range (for the half). One can actually drive a little later but you can get hung up in traffic. I will go out on a limb and say that traffic will not be all that bad this year for any of the three races due to course changes... Saying that, I would rather be safe than sorry. Besides, if you drive, you have a nice shelter.
Spectators.
5k - they should come to the race with you. The 5 k uses a start near the finish line and heads out to the edge of the parking lot then circles back around to a back stage road. so in short, your crew will be able to see the start then head to the stands for the finish.
Half - I would have your crew come to the start with you. They can ride the bus, but the closer to 0400 (last bus) you push, the more crowded and more likely to not allow a runner onto a bus. The crew can hop a bus after the 0400 last runner bus as the buses will run a little longer. However, I find that the race course really lends itself to having the crew head off to the course as soon as runners are called to their corrals.
Pre-race you can hang out together in the staging area. It is also the family reunion area. So while you wait it is a great time to pick out a meeting up point. Once the runner heads through the gear check tent they are in a runner's only area. From there, the crew can walk over to the monorail and head north.
Two real options exist for spectators. The neat one is for them to camp out on Main Street USA and wait for their runner. This lends itself to only one viewing on the course. (two if you happen to catch them in the runner coming out of Cinderella Castle... this is limited unless they have the ChEar Package.
The other option for the half is to camp out at the TTC. Once the runner passes, then they can walk a quarter mile to the Poly or a little further to the GF (Though the DVC construction makes this difficult). After seeing the runner at the Poly, then they can head back to Epcot for a finish.
The spectators should seek a corner where they can stand and see runners coming. This also gives the runner a better chance to see the crew. Make sure you know what everyone is wearing as frankly, all runners look the same and from the runner's side, the crowd is a blur.
Hope this helps