A walking tour in the old city gives you a good introduction to the interesting history and unique atmosphere of Vyborg. The Vyborg Castle built in 1293 and the Monrepos Park and Mansion are worth visiting, just as the Torkkeli Park with its Elk (Hirvi) statue by Mäntynen and Son of the Forest (Metsänpoika) statue by Liipola. Moreover there is the Library building designed by Alvar Aalto that you should not miss.
It is now possible to travel to Vyborg and St. Petersburg with new high-speed Allegro-train or with the exotic night train Tolstoi to Moscow via Vyborg and St. Petersburg. Get onboard at Helsinki, Pasila, Tikkurila, Lahti, Kouvola and Vainikkala railway stations