I have a ticket booked from Vancouver to Portland in August with a three hour break between 11:15am and 2pm in Seattle. I'd like to try and fit in as much as I can (including some lunch) but I'm not sure whether I will can do with my bags - can I check them straight back in or indeed check them through and not have to do anything with them? How much time out of the station will I realistically have and what essential sights should I think about reaching?
Depending on the day and how busy they are, you might be able to just check them in for your next trip. I did it quite early for one from Seattle to Portland as well - very similar trip actually. As you approach the ticket windows, on your left is the baggage check in and the guy will give you a ticket for it.
Alternatively, if they say it's too early, they do offer a checked baggage storage option (click the 'baggage' tab half way down the page).