So...
The simplest & cheapest way from Prague to Liberec is to take a Bus (they call it a bus, I'd call it a coach) from Cerny Most station in Prague (end of the yellow metro line) to Liberec, run by a company called 'Student Agency'. Don't let the name put you off, they're used by everyone in CZ to travel around the country, comfortable seats and you get a free hot drink too. This takes about 60 minutes - the train goes a very odd way and would take up to 3 hours. You can buy tickets for the the busses online, or when you're here at Florenc in the city centre or Cerny Most itself. I'm reliably informed "no one takes the train from Prague to Liberec" - however as the poster above, if you like travelling and have the time then it could be quite a scenic journey in parts.
To quote one of our guys from Liberec, "It's bullsh!t to stay in Prague and try and go back there after the game. Hotels are more expensive in Prague, and Liberec is beautiful town so it´s worth it."
Tickets... sadly it's not going to be anywhere near full. They're not sure yet if they'll sell online for CHL group games, but realistically this shouldn't be an issue. I would suggest if Red Army Travel do any package, or they don't but there's an organised group of a lot of you, we can probably help out with Liberec directly. But the rink takes 7,500, and there's a designated away sector (about 250 seats) so none of the Czechs think it'll be an issue.
In terms of reaction from locals, I think they'll be absolutely AMAZED to see you! Everyone seems to think the idea of hockey in Wales is quite strange (which I must admit I'm struggling with, but to foreigners apparently it's odd!).
I certainly would recommend Prague for a day or two if you have the time, but as my colleagues have informed it could be difficult trying to come straight back after the game - in theory it could go to penalty shots, so you'd just need to allow enough time.