We took a public bus about 10 years ago. They were more frequent than trains.

We are pretty adverse to canned tours from Ship, Viator and other tours although we do look at them to get good ideas. Homework: The internet used to be better with fresh breadcrumbs of people excited to tell the details of how to buy bus, train fares, etc but people are fatigued and many posts are old. So do your homework.

It depends how you and your group are. Do you like someone telling you tidbits right then/there, then get a tour.

We are pretty savvy at getting to a place, hunting for big items, and roaming around for food, etc. We are content with Wikipedia deep dives on what we saw after the fact on the ship or back home.

We like to save money. IOW we are cheap.