Okay, let's see here...
I'd sign up as soon as possible. I believe there is a cut-off point when preregistration will stop (I could be wrong so don't quote me on that). I think it will cost $30-35 for all three days if you preregister. If there is a preregistration cut-off, you can still pay at the door. But warning, if too many people come, there will probably be an attendance cap. The hotel rooms are around $100 if you go by yourself and they usually let four people sleep in one room.
And I do believe there are a number of people from the Tacoma area who are coming down to K-con. If someone doesn't respond right away on this thread, there's an "Anyone from Washington?" thread somewhere around this forum that may help you.