Interesting the twists and turns this thread has taken. Started as a request for a Baltic Sea cruise without Russia. That led to a discussion of GCT's Small Ship Cruising survey. The activity level of various tours was then discussed. And now it seems to be the formation of a future travel group. It's taken on the tone of a cocktail party conversation.
Regarding the activity level of the tours, I can say that the First Mate and I have actually lost weight during each of our GCT tours. The food is good and plentiful, and we did not hold back on our indulgence. But we tried to see everything and do everything, so we did a lot of walking. But I think the only excursion i would not take again is the tour of Marksburg Castle. It was a grand tour and a meaningful experience, but the number of steps, rough-hewn and irregular, that one is required to climb was hard for us, and we were in better physical condition than most of our fellow tourists. In fact, for us, coming DOWN the steps was harder than going up. I don't want to discourage anyone from visiting Marksburg Castle -- it is a "must see". But once was enough. If you go take your time and tread carefully.
We have another couple with whom we have traveled on six of our eight GCT tours, as well as a couple of other sea cruises. It is fun to have others with whom you have a connection traveling with you. When we were in the departure gate at Heathrow waiting to fly to Burssels, a lady walked up and said, "I know you!" This couple, on out Romance of Rhine and Mosel cruise, had also been with us on our Alaska Cruise/Tour a year earlier. Even though we were not "buddies" in Alaska, we were while on the ship.