That's a truly epic post! Thanks so much!
I've just completed UK - Oslo - Malmi - Warsaw - UK, VFR, for the fourth time and often wonder about the St Petersberg possibilities, especially when routing from Kaunas between Karliningrad and Belarus.
Do you think it would be possible for a lone pilot to organise such a trip, or would the administration just be too overwhelming? Were you able to get Avgas in Russia? Without fuel, Malmi - St Petersberg - Tallinn feels a little bit tight for a PA-28 and Baltic weather! I note you had a Russian speaker - is that still essential for VFR? How much of complication were altitudes in metres - or did your G1000 just do that?
Sorry for all the questions!