I hiked the approach to Onion Peak in Clatsop County on Sunday, April 16. You start on the graveled Hug Point Road just off of U.S. Highway 101. The trail follows Hug Point Road and later Onion Peak Road up to the foot of Onion Peak, which is off limits because of the rare onion species on top the North Coast Land Conservancy is trying to protect. It's still a nice 12-mile round trip hike, gaining 2,200 feet. The clearcuts provide for sweeping panoramas of the ocean, and at one point you can see Cannon Beach, Tillamook Head, Clatsop Plains and a sliver of water that is the mouth of the Columbia River.
Summit Post provides a nice description and map of the hike: http://www.summitpost.org/onion-peak/177904
I almost want to sneak up to the top, but I've heard the conservancy has hidden cameras and will charge people with trespassing. There are clearly posted signs at the end of the logging road portion of the hike telling you not to go further. After that, it's a 1-mile, 1,000-foot scramble of the peak, which I haven't tried because of the aforementioned restrictions.