Well, there were no guides- Russian or English when I was at the AP in April of last year. Actually, the place was pretty deserted, except for the babushkas. That is the beauty of traveling off-season, prices are lower and crowds thin. My friend & guide, Nico had the place pretty much all to ourselves. Same with the other palaces. Not the Hermiitage, however. I have been there 4 times now and it is always quite busy. I think Dmitri is right though, Feb. is a pretty risky month weather-wise. Getting around can be a real problem. You must remember Tsarskoe Selo, Peterhoff, Gatchina and Pavlosk are all outside of St.Petersburg of various distances. I was okay in January, but the weather got pretty nasty right after I left. Also, there are not many hopurs of daylight at that time of the year. Flooding is an occurance, and the canals as well as the Neva will be frozen. All the palace gardens are winterised, and not much to see. The fountains are shut down.
I do not know about other's experience, but I had no problem finding ATMs. Usually at the larger hotels, but they certainly were around when I need them. Also, credit cards are becoming more widely accepted at good restaurants and stores.
A word about buying books- if you buy a lot of them. You can, of course take them with you when you leave, but if you have a lot, that could present a weight problem. Another option is to have them sent via the Russian post office. That can take a very long time to get to you, even if you pay for air mail. And third, the major hotels will arrange to have them sent via Finland. Costs a bit more, but worth it for the peace of mind.
I think we all agree that if you do not join a group, you would do best to at least hire a guide and driver to make your viist more enjoyable.