Since there are no actual activities going on thursday, what you can do is really up to you. I like to eat first lol then I like to go to the con center and look for all the areas that each of the shoots I'm attending will be at. I do this so I can get a good feel of the area and see what could make a good picture. I think "hmm, if I have XCharater with he (and I do this with many character situations) then this pic would look awesome!! OH AND THIS!!" And so on.
Then it's time to roam the city. Once I get all my con things outta the way thursday, I decide to go hit up the streets in cosplay just hang out. Last year it was just me and my dad, so we went walking looking for local eateries, stores in case we needed something from one, and how far the mall was. At Akicon last year, (in bellevue) me, him and our 2 rommies decided to walk all over town for like 2 hours..There's tons of things in seattle