We travelled by car (with a driver):
From Riga to Daugavpils on a day trip
From Riga to Vilnius

We travelled by bus with the group:
Around Vilnius
From Vilnius to Panevezys via Kaunas
From Panevezys to Kupiskis on a day trip
From Panevezys back to Vilnius

We took a train from Vilnius to St. Petersburg