We are interested in taking a land tour of the Baltic cities and St Petersburg. Do you have a recommendation for a tour company that conducts small group escorted tours of this region? Thank you.

How small is small for you? Any special reason you want a tour? I've done all the Baltic capitals and St. Petersburg on my own, the Baltic capitals especially are very easy.

I have done a few tours with Rick Steves and can recommend them, although I wouldn't say the groups are especially small:
https://www.ricksteves.com/tours/sca...llinn-helsinki

If you are "of a certain age" there is RoadScholar, although you'd need to two tours to visit Russia as well as the Baltics: https://www.roadscholar.org/find-an-...-and-lithuania

Intrepid has a trip just to the Baltics plus Helsinki, and one that adds both St. Petersburg and Moscow: https://www.intrepidtravel.com/us/ru...baltics-127513

Looks like Adventures Abroad has what you want: https://www.adventures-abroad.com/to...and-russia/bs2