Hello, first time Rick Steves/Heart of Italy traveler. We'll be in Rome ahead of the tour with time to see some of the sights, but since we're not quite sure of our schedule, we wanted to know if we needed to purchase entrance tickets ahead of time for the following or if we could just "show up": Baths of Caracalla, San Clemente, Baths of Diocletian/Palazzo Massimo, Galleria Doria Pamphilj. Any information someone can provide would be greatly appreciated.
San Clemente is our all time favorite. We purchased our tickets in advance. If you are doing the Colosseum & Forum - it is an easy walk from San Clemente.
I have never needed to pre-book Galleria Doria Pamphilj.
Visits to the Basilica of San Clemente is free but entry to the excavations on the lower two levels is 10 EUR and requires reservation.
https://www.basilicasanclemente.com/eng/booking/