I live in Columbus, OH and I've got the same issues with RoadRunner. (I've also used RR in San Diego and it works perfectly on the Mac, which is rather suprising...)
I've noticed that rebooting and clearing the PRAM (Command-Option-P-R) is the only way to make my computer logon successfully.
One other trick is to logon, and then force-quit the LogIn program. This will leave you connect forever, even after shut-downs and reboots.
Furthermore, edit you preference file for the LogIn program to let you retry more than 1 time
Hopefully RoadRunner or Apple will fix this problem soon because it's a real pain.
-- Alex