There are international bus connections to anywhere in Europe, including frequent service to Tallinn and Tartu in Estonia, and Vilnius and Kaunas in Lithuania.
Eurolines Simple Express
Eurolines Lux ExpressMore legroom than Simple Express service & free coffee.
FlybusService between Riga and Kaunas and Vilnius
(http://www.tallink.se) operates ferries between Stockholm, Sweden and Riga.
SJSC Latvian Railways (http://www.ldz.lv/) operates trains to Riga from Moscow or Saint Petersburg, Russia with stops at Rezekne and Jekabpils, as well as trains to/from Tallinn, Estonia via change in Valga. In addition, trains to Daugavpils and Rezekne are available from Saint Petersburg, Russia and Vilnius, Lithuania.
If you travel by train via Daugavpils to connect to/from Riga you might need to stay in Daugavpils overnight for the connection. Therefore, for travel between Riga and Vilnius, it is better to take a bus or plane.
If you have a driver's licence issued by another country of the European Union, you can use it continuosly. Residents of other countries have to obtain a Latvian licence after 6 months; however, it involves only a theoretical exam, which can be taken in English, German, French, or Russian.