Print some off before you go. This time of year they may not have them on hand. Most rangers are pretty friendly but if you find one that is not, just go on to the next park.
http://www.mrsc.org/cityprofiles/list.apsx
http://www.mrsc.org/countyprofiles/profilesmenu.aspx
http://parks.state.wa.us127/Metal-Detecting
http://parks.state.wa.us/DocumentCenter/View/39
