Don't have Waitress advice, but Colbert advice... Just so you know, the taping that I was at, one of the guests ran late and we were let out close to 7:30pm. I know that was abnormal. It actually made that taping extra special, since Colbert and his band The Stay Humans entertained us off camera to fill up the time. But I'm glad I had nothing to run to after.
If she wants to try to get a day-of Waitress ticket, she should definitely buy it before the taping, whether in the morning before she gets in line to get her numbered Colbert ticket, or between getting her numbered Colbert ticket and the return time to enter the Ed Sullivan theater. Personally I had about a 1hr 30m or 1hr 45m gap after picking up my numbered ticket. But we did line up at 12:30pm so we got them right around 2:00pm.
Edited: To clarify, we had advanced reservations to see Colbert. You still need to get in line to get a numbered ticket + hand stamped.
Updated On: 7/23/16 at 11:00 PM