We will have three full days in Rome in October from a Monday to Wednesday (arrive Sunday evening and leave Thursday morning). We have the scavi tour booked for Monday at 9:30 so thought it made sense to visit the rest of the Vatican in the afternoon. Tuesday we would visit the ancient sites and Wednesday had planned on visiting the Appian Way and in particular the Catacombs of San Callisto but now I see it's closed on Wednesdays. Are there other catacombs just as worthy of a visit on a Wednesday or would it be better to rethink our plans? Also wondered whether it's better to join a tour or visit on our own.
The other catacomb San Sebastian is open. Having not been to both cannot judge if one is "better" than the other. My feeling is that catacombs are catacombs and there is not a lot of difference between the two. I don't think you have a choice about a tour and cannot enter the catacombs on your own.
Consider visiting the Basilica of San Clemente in Rome. It's fascinating, being built on previous layers that go back to ancient Rome. Excellent website here: http://www.basilicasanclemente.com/ It was a highlight of our recent trip.
Take one day and relax.......I visited Rome three times, and the last time walked through Piazza Navona and asked myself "How could I have missed this?!" Have a drink and enjoy the magnificent fountain, and using a map walk to Trastavere......... (it's not far) and have dinner there! Then taxi back to where you're staying If you're staying in a hotel near the vatican, the best food I've ever had in Rome is behind the Hotel Alimandi Vaticano........place called Piacere Molise....only Italians, and they will act like they're ignoring you, but that's the Italian way. They finish what they're doing, before taking care of a new task. They don't "multitask" like we do here, serve a drink, seat someone, serve a meal..........
I've toured St. Sebastian twice and loved it both times. You have to wait for an English tour, but there's generally one every hour. The catacombs are awesome, but I agree you need a day to just wander and relax!
Thanks everyone for your responses. Michael, the church looks really interesting so we'll definitely add that to the list. I think we'll see how much gets covered the first two days and then decide on Wednesday morning whether we'll head out to the other catacombs. We are staying in a B&B right by Piazza Navona so we'll be sure to enjoy time there and will definitely check out the restaurant mentioned behind the Vatican.