I have a some links for you, just click on the green letters.
There is not a party there that weekend, but GOMOC is a private astronomy place run by one of the nicest guys around. Call him and arrange a time to meet, He welcomes company on most nights. He also has a running thread HERE.
If you are looking for Washington dark sky sites, THIS website will tell where some places are. I am thinking of going to the Carbon River site that weekend if the snow has melted off in time.
There is a public star party held in Sammamish every second Saturday this summer, it is put on by PLUTO. I have gone to one and it was a blast! HERE is the thread with more info.
Lastly, MSHSP7 is planned for later this summer! make sure you read to the end of this thread for the latest info.
-------------------- Celestron 15X70 binos
Zhumell 10" "Photon Cannon"
Baader Hyperions 5mm, 8mm, 13mm, and 17mm, + FTR's
70mm Meade refractor on "broken" 494 Autostar tripod
6" F/8 "Ellis" 50 Year Old Newtonian Project!
AEACC The Automatic Electric Aluminum Can Crusher thread