Hope I am not too late replying to your question concerning excursions for the Baltic.
Be carefull booking, probably the best is to choose from home and book via internet. Not only now you have the time to read about the different excursions and make your choice, but the queuing on the ship at the Tour Info is terrible!!! You can better enjoy your cruise in stead of waiting in line.
Also be carefull booking too many excursions. Not only can that be very tyring, but sometimes you will not make the next excursion because the first arrives too late at the ship!!! Needless to say, you never get your money back. Before everybody now gets irritated with me: no it did not happen to me. Sadly it is usual older people who believe the stories of salespeople (excursion buro) and sadly it is older people who would have loved to go to the ballet, but they just couldn't make it.
For instance: at St. Petersburg the afternoon excursions leave approx. 14.30/15.00 hrs. and return to the ship approx. 18.30 hrs. When you have also booked the excursions for the ballet in the evening you must leave at 18.45 hrs. Impossible!
I tried to explain to the Tour Buro they could at least point this out in the info, but they refuse and happily receive your money for excursions you will never be able to meet!
Also when an excursion doesn't work out, they don't handle complaints and refuse to deliver a complaint form.
Luckily there are other options to be heard, so we didn't make to much fuss about the complaint but handled it back at home so we could enjoy our cruise in stead of standing in line of a company who doesn't wish to listen to customers.
Don't let this put you off! We especially enjoyed the bustransfers and explored the cities alone.