Cruisefan 999 is so right. We did the Baltic a couple of years ago. You will have fun just walking about in Stockholm old town and "new town". They are side by side. We found a great beer garden there which served the best Swedish Meatballs with lingonberry jam. The BEST!
I say this because you are "anti-excursion"
(we are too). In Talin, disembark the ship and walk through the parking lot towards the right of town. The name of the gate is, "Fat Margaret". Here is a picture of the gate you will walk through:
You can easily spend 3 or 4 hours walking the old cobblestone streets of Talin, there are many shops, pubs and cafes. There is a restaurant, you walk in and it resembles an old farmhouse kitchen. There pictures of pink pigs above the restaurant (I forget the name)...very excellent authentic Talin food...we had hard peach cider there, french fried bread with garlic and split pea soup...so very good. Found a shop that sold Swarovski there, and it was actually a little cheaper.
But definitely do Talin and Stockholm by foot. No need for a tour.
In stockholm, take the Celebrity bus to downtown and do NOT miss the Royal Changing of the Guards. For us it was so much better than Buckingham's. You'll enjoy the procession (horse and carriage for the King and Queen and a Bently for the Prince, lol)!