Ecola State Park has mile after mile of trails. Included is the Clatsop Loop Trail. This trail that takes hikers in the footsteps of Capt. William Clark.
Cannon Beach is delightful in itself but nearby is this state park and its absolutely charming. Every time we have been there there hasn't been very many people so it's nice to have it all to ourselves. There is a fenced walkway that brings you all the way to the edge of the cliff and you can see the small town of Cannon Beach. I suggest bringing a bagged lunch and watching the sunset.