You really can't make a mistake doing the Oregon coast at any time. Fall is likely best, but for those that cannot go then...it's probably like the eastern seaboard....no really bad time.
There are chains like Mo's that find favour..and then there are the small mom/pop joints that just about make your hair stand on end for good food and happy people.
If you are into oysters and beer...you could be eating fresh oysters and quaffing a cold one first thing in the morning with the locals..and I happen to think that that is one of lifes blessings. Lots of craft beers to be tasted. If you enjoy wines, Oregon has a famous industry.
And if it is raining...you put on your wet-skins and go walking on the beaches, hang out on the bridge in Depot Bay and try to avoid the breakers/wind combo, watching the USCG training boats out on the break. There are several cheesy places...Tillamook and Bandon. Almost every small city-town along the road has a beach view. There are lots of breakwaters that give safe passage for the small boats that access the sea. Plus the surfers that inhabit those same areas.
The best suggestion is to take your time. The cool stuff is around every turn. Get off the 101 at every opportunity and go exploring. you can quite easily invest a week...7 days...if you can just kick back and cruise around.
Oh..and take an electric heater with you. If it's a wet trip, you'll need to dry your stuff and so on.
http://youtu.be/zs4uQ_HBfXcGary Haupt