1. Saddle Mtn hike (about 30 mi from Cannon Beach)
2. Wading in the tide pools around haystack rock
3. best restaurant in cannon beach: the bistro. perfect soups. delightful wines. good fish entrees.
4. shopping for artsy craftsy things in CB is fun. Some good deals to be had.
Quick Tips:
go in the off season. in summer cannon beach is crawling with yuppie tourists from portland, crowding the streets with their SUVs. in the winter time you can storm watch, hike through some great blue snow, your don't need reservations, and the service is all around better.
Best Way To Get Around:
you will likely need a car. cannon beach is spread out down one long main street. plus if you want to go to ecola state park or up and down the coast, you will need to drive there. I don't think there is any public transportation. You can easily cycle around Cannon Beach if you bring your bike with you.