The full and maybe the Goofy challenge might last a few weeks or a few months,for every other race I would try to be at your computer at noon the day it opens(April 19 for AP and DVC,and April 26 for general registration).The smaller races pretty much always sell out almost immediately,the half if I recall usually also goes fast,I think this year it lasted longer than I expected but since its the 20th anniversary in 2017 it will go fast,probably in the first couple of hours.The Dopey challenge has shown to be really popular and always goes fast.The full usually lasts a few months,like well into the summer,Goofy will also last for awhile as its still popular but the logic behind many runners is that if I'm going to run a half and a full and get 3 medals and 3 shirts it seems smarter to also throw in a 5K and 10K and get 6 shirts and medals for doing the Dopey instead of Goofy.The whole point is that if she wants the half she should sign up ASAP or the only options to do it will be to sign up for the Goofy challenge or go through a charity.