The early run through Epcot was my favorite part of the old course. Has anyone ever gotten a good answer on why they removed that portion? I can't think of any logistic issues other then having us being in the parks that early and maybe not wanting to have to staff that section of the run or getting us into and out of the MK quicker but I don't think either of those two things was a big problem that needed solved.
I never did the course that ran on the speedway but have done the Indianapolis Mini Marathon which runs on the Speedway there and as cool as it sounds you realize when you are there that running at a 7:00 through 15:00 minute pace through a facility designed for 200mph driving is just daunting and kind of boring. It feels like you aren't actually moving. I imagine the Disney speedway was much the same.