FINLAND via ESTONIA, LATVIA, LITHUANIA to POLAND
I you want to visit the Baltic Countries, you can not do it by InterRail. But it is really cheap to do this kind of exotic journey.
In total you will pay from HELSINKI (Finland) via TALLINN (Estonia), VILNIUS (Lithuania) to WARSAW (Poland) EUR 50,-
Off course you have to pay something extra if you want to stay in hostels or do some extra journeys to the sea.
For example from VILNIUS (Lithuania) to KLAIPEDA (Lithuania) directly at the sea with magic white beaches you have to pay EUR 14,- one-way by train.
The hostels ( https://hostelworld.rail.cc ) are extremely cheap (good ones for about EUR 10,-), the food and night life as well.
HELSINKI to TALLINN by ferry: it is a journey of 2 hours. And if you avoid peak times like weekends, the ferry will be EUR 20,-. At peak times it can be up to EUR 35,-. So pay attention and ask at the office for the low fare tickets. More details: Tallink Silja Line - http://www.tallinksilja.com/en/
TALLINN via RIGA to VILNIUS by bus: it is a journey of 9 hours for EUR 20,- to 30,-
More details: Eurolines Estonia - http://www.eurolines.ee/en/
VILNIUS to WARSAW by train: take the day train (there is also a nigh bus available). You have to change at the Lithuanian-Polish border at Sestokai. For the Lithuanian part ( http://www.litrail.lt ) of this journey you have to pay EUR 7,-. The Polish part is free as you can use your InterRail ticket.
From Warsaw you have direct access by train to the whole Eastern Europe as well to Berlin (Germany) and even Switzerland.
details: https://en.rail.cc/from-finland ... y/10293/15