How to get to Lithuania?
Coming by bus
The cheapest way to travel to Lithuania is by bus (Eurolines, Ecolines etc.)
You can take a bus to Lithuania from pretty much all over Europe, even from as far as Portugal, UK or Norway. Of course it takes a long way to get there, but normally you don’t have to change so often and the prices are really smaller than that of trains. Coming to Lithuania by bus from Portugal takes about 48 hours and costs about 267€ both ways (check your national Eurolines office for more information about prices from your country).
Bike on bus
Official Eurolines policy is not to take a bike on a bus. However, I always managed to get mine on board (once I even carried 2 bikes with me). The trick is to put your bike in bag (just take of the wheels, normally that is enough). You can get such bike bags in you bike shop (don’t buy padded, heavy bike bags, you will have to carry it with you during the biketour!) or you can also make one yourself (as I did). Another idea would be to put your bike in carton box, but it becomes a bit complicated to transport it.
The main thing to remember about bike bags is that most of the time you don't have to use them as a carrying case for the bicycle. The only real purpose of the bag is to make the bike look like a package so you can get it past the baggage-taker at the bus station. You normally have to pay extra fee for big luggage (5-10 euros).
However, in this case it is really not a good idea to travel in big groups! 2-3 bikes per bus is already a lot.
Coming by train
Coming by train to Lithuania might be easy and fun, but it can become a bit complicated if trains get late. There are only two train connections to Vilnius from Warsaw:
07:19 (Warsaw Centr.) – 17:53 (Vilnius) [from may 13 to june 18 this train will leave few minutes earlier, check bahn.de]
23:00 (Warsaw Centr.) – 09:00 (Vilnius) – this one is actually a bus instead of train.
If your train is delayed and you arrive to Warsaw after 07:19, you can go to Warsaw Zach. and take a Eurolines bus from there:
09:30 (arrives to Vilnius at 19:30)
18:30 (arrives to Vilnius at 06:30)
It is really a good idea to have a bike bag with you just in case. And always double check for schedule changes!
Attention: If you look for train connections to Lithuania online (best is bahn.de), make sure that your train connections do not include Belarusian cities - Minsk, Gdansk, etc, as you would need visa to go via Belarus.
Bikes on trains in Lithuania
You can take your bike on any train (there should be some speacial bike places in last and first car of the train). You have to pay 2-7 Lt (0.6-2 euros) for a bike at the ticket counter. If you decide to unpack the bike and your total baggage doesn't exceed baggage limitations (up to 50 kg), you can take your bike on board for free.
Coming by ferry
If you live somewhere close to the Baltic Sea, you can also come by ferry to Klaipeda and then take a train or cycle to Siauliai. You should be able to take a ferry to Klaipeda from Kiel (Germany), Karlsham (Sweden) and Aabenraa - Aarhus (Denmark). I could not find a reliable website for prices and timetables, so best would be to contact nearest travel agency and ask for all this information.