Travel / Holiday in Poland (question about transport by bus from Riga) [7]

Hello.
I'm going to spend August in Poland and I have some question about transport. I think I'll come to Warszawa from Riga by bus. Then I would like to go to Krakow (there will be good concert) and after that go to Gdansk. What is the cheapest way to travel in Poland? I heard that PKP train is one of the cheapest. I found this site booking.polrail.com and I can buy tickets now. But is this site safe? Maybe would be cheaper to buy tickets in Poland's station than online? Or which online tickets store are cheaper and more safe?

Also, which cities you recommend to visit too?

Thanks, Egle

Travel / Help to reach a place in Warszawa (Warsaw), Wilanowska 14, to go to Krakow? [4]

Hello,
I need some help about public transport in Warszawa
I will come to Warsawa around 22:55 in the Aleje Jerozolimskie 144
And I want to go to Krakow from Wilanowska 14. My bus to Krakow go around 23:45
What is the fastest way to reach Wilanowska 14 ? How much time it last? Is it possible too be on time, around 23:30?