Michaelson,
I don't think you'll be too late. More like right on time.
You may be right about the last frost date, but I doubt it. In Olympia at least our last frost date is mid-late May; you are in the Rain Shadow but I still would guess it's in May. Check out the Maritime Northwest Garden guide for more info on last frost dates.
http://www.amazon.com/Maritime-Northwest-Garden-Guide-Elliott/dp/0931380189 This is also a great guide for what to plant when. Whenever I think I'm behind I check this and I have something to compare with. You could easily show up in April, make your beds, head down to the farmer's market and the co-op, buy seeds (direct stuff like beets, carrots, etc.) and starts (brassicas), and be on your way. Consider getting Remay and Sluggo for cold wet nights.
If you need very regional help, I recommend
Vegetable by Vegetable: A Guide for Gardening Near the Salish Sea. It's available from Uprising Seeds (
http://uprisingorganics.com) and likely bookstores in PT and probably the Co-op; it was written by Marko and Hanako of Midori Farm (
http://www.midori-farm.com/) who also
sell starts at the PT farmer's market. They wrote the book to
answer all the questions they were getting at the farmer's market.
If you're new to gardening I strongly recommend
Growing West of the Cascades by Steve Solomon. This book has some instructions on how to start beds too.
Good luck!