Originally Posted by Dave.
So do I, but that is one long train.
I'll be in Stockholm and I definitely want to take the ferry across to St.Petersburg, but I don't know if I'll have enough time to fit Moscow in and make it worth it. Plus I kind of have Tallinn in the back of my mind for this trip as well. So who knows.
If you don't have time and if that's what you're doing, maybe just do Saint Petersburg. There's a lot of things to do there. Plus if you're interested and want to go out to Peterhof gardens, Catherine Palace etc.. that's a day trip in itself.