If anyone is still looking for a place to stay Savannah Marathon weekend, I can no longer go to the race and would happily give you my booking. I had a small carriage house booked for Thurs-Sun (they only do 3 night rentals) within walking distance of the race start and party location. You would just take over my reservation and make your own booking with them. Total including taxes/fees was $617.
Feel free to email me directly at emt409@gmail.com
This is the website of the rental with pictures:
http://staysavannahvacationrentals.com/midnightinthegarden.html