Torfyanovka-Valimaa border crossing
Simply ask drivers at the parking lot by one of the supermarkets around there on the Russian side.
On the Finnish side, just before the customs zone, ask drivers at the petrol station. You can also ask drivers on the parking, and those queuing to the terminal. A ride to Torfianovka is enough – there's lots of transport going to Vyborg and Saint Petersburg from there.
As of 2006, it was a complete waste of time to hitch a truck over the border to Russia – the freight terminal is separate for trucks and the queue there is extremely slow, with drivers waiting many hours or even days to cross.