Prune Hill is an extinct volcanic vent, 755 feet ASL, located in Camas, Washington, about 30 minutes from Portland, Oregon. This summit is in a suburban neighborhood with no public space near the summit itself. 

Dorothy Fox Park to the northeast is within the activation zone. The closest address to the summit appears to be 2702 NW 18th Avenue, Camas, WA 98607.

The ball fields of the LDS Church near the summit are not available as an activation site. 

Prune Hill is mentioned here:  http://en.wikipedia.org/wiki/Camas,_Washington.