hi there, two of us did the train thing last year and it worked out well. we got to leszno in plenty of time for the gp and arrived back in wroclaw at about 1am, train journey if i remember rightly aprox 1hr 30 mins anyway i have a link for the polish rail service here http://www.intercity.com.pl. or email this guy he helped me out no end last year Polrail Service-Jeffrey Dobek [jdobek@polrail.com] i ordered the tickets online and they were sent to me in the uk so i knew i had the tickets before i travelled. i also find it best to travel first class as it is more comfortable and the second class carriages can get busier with locals on the journey back to wroclaw and rail travel in poland is cheap as chips
http://www.polrail.com/
Polrail Service
ul. Kujawska 48/33
85-031 Bydgoszcz
POLSKA
these were the train times for last year so i cant see them being to much different this time round
Travel from Wroclaw to Leszno, Saturday, 09 May 2009:
* Train #P38102
* Depart Wroclaw Glowny 1035
* Arrive Leszno 1210
* 1st class, unreserved seating
Travel from Leszno to Wroclaw, Saturday, 09 May 2009:
* Train #D83510
* Depart Leszno 2356
* Arrive Wroclaw Glowny 0135
* 1st class, unreserved seating
Travel from Leszno to Wroclaw, Sunday, 10 May 2009:
* Train #P83706
* Depart Leszno 0300
* Arrive Wroclaw Glowny 0432
* 2nd class, unreserved seating (train is 2nd class only)
i hope some of this helps, enjoy your trip and maybe bump into you there as we have decided to stay in leszno this year but are flying to wroclaw and will be spending the friday afternoon there before travelling to leszno early evening.