My wife and I (mid 70s)recently spent a week in St Petersburg on our own, wanting more time to see everything we could than allowed by cruise ship schedules and crowds. Guided tours seemed expensive but the one we took with Best Guides to Catherine's palace and Pushkin was more than worth it. As prearranged by email, our guide Inna and driver showed at our hotel at exactly 10a.m. and for the next 8 hours met our every need. Inna teaches English (and French) at the university and speaks it fluently and shared her own life's experiences. On the way out a lot of things were pointed out and she even stopped at a pharmacy to help me buy cough drops. We skipped lunch to see the palace (admission included) free of mobs (including the Amber room-only place where photos were not allowed) and all of the park. We stopped at the massive memorial to the defenders of Leningrad but even more impressive we got to the Piskaryovskoye
Cemetery which was very moving. We later combined a different tour offered thru our hotel of the Peter and Paul Fortress and cathedral with drop off at airport but this guide was not as good as Inna, and we could have done that on our own. Perhaps other than having two days by ourselves in the Hermitage this trip to Catherine's Palace was the best part of our week. Inna even made some good restaurant recommendations and did not include the annoying mandatory trip to a souvenir shop that our hotel tour included.