Thank you for your response. I should have mentioned this is Greenville North Carolina not South Carolina. Sorry.
During previous visits Pitt Co sheriff has provided the escort for the motorcade and street closures, I would check their TAC or event channels for traffic. Don't forget airport police frequencies/TGs.
That said, if help is needed, they may ask the assistance of the NC SHP which will use Statewide Events TGs and the SHP Motor TG on Viper.
While USSS frequencies are typically full time encrypted there are the seldom times when they aren't, they are worth having in your scanner. The most common for a VP visit is channels Charley, November, Sierra, and Tango, all available
HERE.
Typically, there are no special air frequencies used by AF2 and during the VP visits, they use the standard airport and ATC frequencies. Also don't forget that AF2 can be tracked using
@AirplanesLive website
HERE.