In January 2005 we decided to go to disney literally on monday, left Wednesday and stayed til Sunday. We didnt realize until we arrived that there was a marathon going on. Someone actually scared us on the Mears bus on the way over saying its 40,000 people, etc. Until race day when we were in the AK and you had to cross their path to get to the Dinosour ride, we wouldnt have known they were even there. Many of the runners were staying at AKL and were in the lobby after the race, didnt find it at all inconvenient and the parks werent crowded at all. Dont be discouraged like I was when i heard 40,000 people, they really do not interefere too much with Disney itself even though a few roads were closed it was very clearly marked.
, so we ended up entering the park in the midst of the marathon. Not the best idea if you wanted 'easy' access - but we went with the flow and ended up having fun cheering the runners from the boat and when we finally got into MGM there were a lot of characters there cheering on the runners - it was hard to get around for a while though. We managed to get over to RnR and Tot and then to Prime Time for lunch - by the time we finished lunch it was all over! The weather that week was in the 50s-low 70s during the day - high 30s to 50s at night - we did have a couple of windy nights where even the big kids were glad that I had packed headbands for their ears and stretchy gloves (and the plastic raincover for DGrD's stroller kept her snug and warm !) 
