Trying to make a few plans but our itinerary is so vague about where we will be staying! Where did you stay while on the Best of Italy tour while in the Dolomites?!
When we did this tour in 2017 we stayed in Castelrotto. I know other more recent tours have stayed either in Bolzano or further up in the mountains like Castelrotto. It undoubtedly depends on what hotels they're able to secure for the group. We're dealing with the same vagueness for our Alpine My Way tour next June, but the Dolomites are so gorgeous I'm sure we'll be happy just being there.
I just got back from the Dolomites this spring (I went for skiing) so I will add some reassurance although I have never done the tour. It is not that big an area and each hotel gives you a Mobipass for local buses so you can go up one lift and hike or go down another and get home easily. The buses go everywhere., and I am sure your guide will provide lots of details. The Alpi di Susi can be reached by gondola from either Seiser Alm or Ortisei and a bus connects the two. Buses run very regularly from Bolzano/Bozen to Oritsei and along the Val Gardena from Ortisei eastward to Santa Christina and Selva, and over the Grodner Joch (pass) to many other towns including Cortina d'Ampezzo. And back.
Don't get confused by the fact that all of the towns in the South Tirol have three names - A German one - Kastelruth, an Italian one - Castelrotto, and a Ladin one - Ciastel. The Ladin ones were added during the pandemic and are not yet shown on Google maps for example.
If you are a keen hiker consider consulting Gillian Price's hiking guides to the Dolomites.
Have fun!