Is there a direct bus route that travels from Rome to Sorrento during the summer?
I doubt directly. Rome/Naples with a change to Sorrento much more likely.
There is. I think it runs twice a day. I cannot remember the web site so goggle Rome/Sorrento/bus
Roy, You might check the websites for Curreri Viaggia or Marozzi Bus lines. They usually offer trips from Roma Tiburtina to Sorrento, possibly with a stop in Naples. Happy travels!