I'll be there too...it's a really fun race. I run many races throughout the year, but this is always my favorite since you run the last half through the park.
As for being swept off the course for a slow pace, I've never seen this done. However, this year there are EMH at HS at 8AM (I can't remeber if they had them last year too or not), so that may be an issue for someone going really slow. You run right by the main gate at the end of the race, so as long as you get by there by 8AM, you should be ok! To bad I can't stop by Toy Story Mania and get a fast pass during the race!