bus route/line 53 in Rome

Looks good to me, but I did not verify all of your stop numbers. Here is the link to the 53 on the ATAC Rome website which is official. However, buses often go on temporanea routes because of road work or other "events" that interrupt the route, so one never knows.

FWIW we like the PROBUS application on our phones. Note, though, that the ATAC feed of bus arrival information -- whether to PROBUS or their own feed -- can be misleading. It tells you when buses are arriving (if the GPS is working) but that does not mean they are in service. You may see on the app two #53s arriving at say 5 minutes and 10 minutes, then all of a sudden only one is left at 6 minutes because the first one went fuori servizio a stop before it got to you. I could tell you bus stories!

If you are going Colosseo to the Borghese, you can also take the Metro to Barberini and walk 15 minutes to the gallery.

Buon viaggio!

Thank you for the information. Our trip is coming up soon.