We brought our own car to Lithuania and visited both Lithuania and Latvia. (We travelled to Klaipeda by ferry from Kiel in Germany.)

The roads are generally good, but we had trouble getting into the town centre from the port - a no man's land with no signposts.

You MUST take out special insurance to drive in Lithuania -it will probably be part of your car rental costs, if not you MUST buy it at the frontier - it's Governmental controlled, and you risk untold hassle if asked to produce it by the police, and can't .... and that's assuming you are not fluent in Lithuanian!

For Latvia, you must drive with dipped headlights on at all times.

Do not drink and drive - tolerance is zero, and you might well find yourself at a disadvantage linguistically also!

Oh and PS, if you were hoping to drive down the Curonian spit to the Russian bit .... NO WAY will the Russians let you across the border!!

Thanks for your comments Alsalienne, very much appreciated. I was certainly unaware of the zero tolerence re drink/driving. also the tip about headlights is useful.