Hi Heather! The Princess Half marathon is the perfect race for a group of girlfriends! You guys will have a great time!
Saratoga Springs is not listed as a host resort (offering buses), so you would need to find alternative transportation to the race. You may have your own vehicle, or you can always arrange for a cab. I have traveled both ways before to races. While it isn't as convenient as the Disney buses, I have never had any trouble.
However, I do advise that you leave really early on race morning. There will be road closures (maps will be available at your front desk) and the traffic will be heavy as it gets close to race time. I like to leave my resort by no later than 3:30 a.m. if I am driving. I just plan to eat my breakfast at the starting area. There will be food and drink vendors there, along with tables to sit at. Being there early helps to calm my race nerves as well! If you haven't already, check out the
Race Retreat package. (scroll down to the Race Retreat information) It is a little expensive, but the tent is a great place to hang out (and stay warm) before the race.
I hope this helps! Please let me know if you guys have any more questions leading up to the race!