Well Seattle/Tacoma works for me - only 2.5 hours by Vette!
I think Tacoma would be preferable over Seattle. Lots of museums, including LeMay and museum of Glass (Chihuley). My wife and I had a weekend up there a year and a half ago to see both of those. LeMay had a 'Vette exhibit going on at the time - fantastic. Tacoma also has better access to Mt. Rainier - lots of good drives in that area.
If a small town is desired, I'd suggest Packwood, WA, on US 12 between Chehalis and Yakima. They have a number of large events every year, including a big rod run - able to handle an influx of "car types". Also it's a great gateway to Mt. Rainier National Park and a pretty easy drive to the Yakima Valley if folks were interested in wine tasting.
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1976 Silver/Firethorn. L48, 4spd. Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.