Deep lake in King county is open year round. I really like fishing there, nice lake but don't know it well, but have good luck with worms from Cumberland store. I have not fished it yet this year.
Here is the web site that tells you about what's in it.
http://www.washingtonlakes.com/king.htm#Deep%20King

Here is when, what and how much was planted in the lake this March.

http://wdfw.wa.gov/fish/plants/weekly/c040318.pdf

And because of the depth, up to 100ft, I think that somewhere in there has got to be one mother of a fish