Taking the train is a great way to avoid the $20 parking charge at the Arena as well as the issues with traffic flow before and after the game.
We went to the men's game last month. At 11:20 am (for a 1:00 pm game), traffic was already backed up for about two blocks near the Arena parking lots and garage (not onto the highway or exit ramp at that point, although it did happen later). There were some reports of people being in traffic for almost an hour before parking.
If you plan on parking at the Arena, plan extra time to deal with the traffic. We found street parking spaces downtown for the NCAA regionals last year and the men's game without difficulty. The walk is a few blocks and the temperature will be in 40's this weekend!
Go Huskies!