Hi, Michelle!
Thanks for visiting us here on the Disney Moms Panel.
Karen P. is currently on a well-deserved break, and since I ran
Disney's Princess Half Marathon last year, your question was assigned to me. (I hope you don't mind, and I will tell Karen you said, "Hi!")
For the half marathon weekend, the influx of thousands of runners and their families will be offset by the typically low crowd levels experienced during a non-holiday weekend in February. More than likely, it will not be as significant as the crowds experienced during the spring and summer.
Just so you know, runners typically don't like to wear themselves out by visiting the parks prior to a race but may hit the parks afterward in order to keep moving and not allow their muscles to get stiff. Therefore, a good plan may be to hit the parks the day before the big race and avoid them the day of. Yet, I still think you are going to see minimal impact.
Make sure you congratulate the race finishers...they'll probably swagger around the resorts and parks with that bling hanging around their necks! I hope you have a wonderful day and a magical vacation, and should you ever decide to take a
Disney Cruise...I'm your mom with those answers!
Andi