Closest is Summit, then Stevens, then there's Crystal south and Baker up north. Different people will claim different mountains are the best. For your uncle, if he's pretty experienced Stevens would probably be his best bet. I prefer Snoqualmie (summit) only because its closer, and I grew up skiing there so its my home mountain (and passes are cheap there).
Snoqualmie is about 45 minutes from Seattle, Stevens is about 1.5 hours. Baker and crystal are both about, what... 2-3 hours?
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that makes your velocities shiza high