Via Appia Antica (Appian Way)

Hi there -
We've walked that stretch between Casal Rotondo and San Callisto and then beyond to Porta San Sebastiano and then Baths of Caracalla and some churches. The section you're looking at covering will be closer to 3+ miles, and there is a lot to look at along the way so I'd estimate it taking a fair amount of time. It did for us, anyway. My camera got a workout!

The park's website gives the distance between Tomb of Cecilia Metella and Casal Rotondo as 4.5 km (2.79 miles). You'll be adding the distance from San Callixtus/Callisto to Cecilia Metella (closed on Sundays) so that's what I'm basing my estimate on

https://www.parcoappiaantica.it/itinerari/la-via-appia/

If you haven't found it yet, here is a great printed guide - in English - of notable landmarks along the way and a bit about them. Don't use this for hours/entry fees of attractions along the way; pretty sure that info is out of date but the rest is useful.

https://www.parcoappiaantica.it/wp-content/uploads/2016/05/AppiaAntica_eng_2015.pdf

The ''worth" question is always tough but we were glad we'd visited the Maxentius complex. As the park lists it as closed on Mondays, I'm just not sure you can access the site even though it's free.

https://www.turismoroma.it/en/places/villa-maxentius

And honestly, there is not a ton of visitor services along the way. We used the facilities located in a small separate complex at San Callixtus (which we didn't visit) en route from the catacombs of San Sebastiano (which we did) and had an OK cappuccino from a vending machine there. HA! There are a couple coffee-cup icons on this map on the park's website - one near the visitor center near the church of Domine Quo Vadis, and another near Capo Bove - that indicate places for a cuppa joe.

https://www.parcoappiaantica.it/wp-content/uploads/2016/05/Guida_Turistica_ITA_2019.pdf

One between Capo Bove and Cecilia Metella is Caffe Appia Antica; Via Appia Antica, 175, Roma. Looks darn pleasant!
https://appiaanticacaffe.it/en/home-en/#!/services
https://www.tripadvisor.com/Restaurant_Review-g187791-d3604614-Reviews-Appia_Antica_Caffe-Rome_Lazio.html

Don't know if this is something you'd be interested in, but I did a bike tour of the Appian Way and loved it. We stopped at a few of the catacombs and the Maxentius ruins, among other stops. We went all the way to the Park of the Aqueducts. I believe I booked it through "Get Your Guide".

Glad that worked for you, Katie!
Just a mention that Get your Guide is a 3rd-party marketplace for tours and activities that are conducted by other companies, often at a mark-up. It's often recommended to book directly with the company who handling the activity/tour in case of a complication that can result in a finger-pointing battle over who is responsible for making things right, and/or a better price.

Regarding doing the thing on two wheels, this review from a frequent RS poster:
https://community.ricksteves.com/travel-forum/italy/biking-on-the-appian-way-be-forewarned

Kate and Katie - thank you. I relied (ha ha) on ChatGPT for the distances. It's just weird that I can't find a map of the Appian Way with distances between sites marked on it. I'll probably have to shorten the walk to just San Callisto to Cecilia Metella (with Maxentius included). An extra 4.5 km to Casale Rotondo (and even more to Capo di Bove) just isn't in the cards. Next trip, maybe! Still a tour of the Catacombs of San Callisto, a peek at the Basilica di San Sebastiano, exploring the Circus of Maxentius and Tomb of Romulus, before hitting the Mausoleum of Cecilia Metella is a pretty good run.

An extra 4.5 km to Casale Rotondo (and even more to Capo di Bove) just
isn't in the cards.

I'm a little confused. Look at a map? Capo Bove isn't farther than Casal Rotondo: it's not really all that much farther along than Cecilia Matella. It's Casal Rotondo that is at the far southern end of the things on the road you had on your list: go no further than Capo Bove and you probably could do it in 2 hours. Or have I misunderstood?

But again about the Maxentius complex: they are listed as closed on Mondays, and it is gated so you can't just wander in to see the ruins from more than the road. Same with Capo Bove, I believe. I might suggest a virtual walk via google of the stretches you're looking at doing if you haven't done so already? And you already know to walk Ingresso Catacombe di S. Callisto from those catacombs to the catacombs of S. Sebastiano instead of the parallel stretch of the Appia, right?

You are correct about the order. Chat GPT had it wrong (don't trust AI!). It appears that circus of Maxentius and Capo are closed on Mondays

I should be able to walk to San Sebastiano (yes, along the ingress road) and from there to Circus Maxentius (no entry - just what is visible from the road) to Cecilia Metella (exterior only) and to Capo di Bove in little more than 45 minutes.

There's really nothing open on Mondays in Rome!!!

There's really nothing open on Mondays in Rome!!!

Really? The Colosseum/Forum/Palatine are open, as are the Vatican Museums, the Capitoline Museums, Museo dell'Ara Pacis, Doria-Pamphilj Gallery, the Pantheon + most of Rome's fabulous churches, and I could probably find more if I went looking for it. :O)

While I know you don't have the time, we thought the stretch of the Appia from our jumping-on point at Casal Rotondo to Cecilia Metella was the most pleasant to walk. We felt like we were really removed from the city, and there were lots of interesting monuments along the way. I'm glad you're doing one of the catacombs though 'cause they provide a very interesting background of burial practices in the 2nd - 5th centuries or so.

Actually, I've just confirmed that Santa Cecilia and Santa Maria in Trastevere are open on Mondays. I'll just do my Trastevere afternoon on Monday and move the Appian Way to Tuesday. Problem solved.

Yay! Sounds like you've gotten it all worked out!
As you're interested in churches (the mosaics in SM in Trastevere are killer, BTW) I'll throw these out for Monday as well:

Chiesa di San Francesco a Ripa is just a bit south of Santa Cecelia and has Bernini's last sculpture: well worth stopping by.
https://www.sanfrancescoaripa.it

Posted hours on the website above are 7.30 am – 12 pm, and 4:00 PM – 7:30 PM. They do have daily mass weekdays at 7:30 and 18:30 so I'd plan my visit around those, and Sunday hours are different.

Just across the river (cross it at Ponte Sublicio) and up on the Aventine, is the Basilica of Santa Sabina: a very old and important lady with a loooong history.
https://www.turismoroma.it/en/places/basilica-saint-sabina-allaventino
https://basilicasantasabina.it
Visiting hours are Sunday to Monday: 12.00 – 19.00. The Orange Garden (Giardino degli Aranci) next door offers a nice view and great spot for a sit-down with a packed-along snack.
https://www.turismoroma.it/en/places/savello-park-or-orange-garden

Another treat - especially in May - is that just a bit down the hill from S.Sabina and the orange garden is Rome's municipal rose garden (Roseto Comunale) which we visited in May (the month you'll be there) and on a piece of ground with an interesting background. It's free for the wander and offers a great view of the backside of Palatine Hill. Its fun little link to the US is that it in 1950 it became the new home to roses previously located in Parco Colle Oppio, and which were given to the city by a former Pennsylvanian, Countess Mary Gayley Senni, in 1932. The international Primo Roma contest is held here every year abt. the 3rd week in May.

Flora, the Roman goddess of flowers, once had a temple up here. Fitting, don't you think? 😉

https://en.wikipedia.org/wiki/Rome_Rose_Garden
https://www.turismoroma.it/en/places/rose-garden
Visiting from Monday to Sunday from 8.30 am to 7.30 pm from abt. mid April to mid June, although flowers will be at their best in May. Beautiful!
(Edited for a spelling error + additional info link)