Does anyone have suggestions on making alternative activity arrangements on Sorrento, Taormina, Rhodes, Kusadasi, or Santorini? I have read that the cruise line (Radisson in this case) activities are wildly overpriced.
I took a med cruise that went from Turkey to Spain, so I can't comment directly on the specific islands. What I can tell you is that while I didn't find better priced tours on shore (I was on Celebrity), I did find better tours. The best tours we took were with private tour guides - which we booked for the 5 of us.
It made a big difference avoiding taking those huge tour buses with 200 others. We got off the boat faster, we saw exactly what we wanted to see, and we sometimes managed to avoid the crowds.
That was a few years ago, but it might be worth it to check out individual tours rather than the ship-run tours.
I can only comment on Taormina. I suggest you take the funicular up into town and tour the greek theater. Walk around. It is a much bigger town that I originally thought and there is plenty of shopping if that is your thing. There are plenty of places to buy a cameo. They are known for them in Sicily.
Have a good lunch, maybe take the bus up to Castle Mola to have a granita and enjoy the view. If you go to the public gardens you will have a good view of the island from there as well.
If you go into the information center they have maps of the town. You can see everything on your own very easily. The bus station is down the road from the funicular, by the way.