There are many iconic locations, some of which have been already mentioned. You do not mention where you're coming from and where you'd like to go. You also do not mention what you'd like to photograph, so specific locations are hard to recommend. The coast is over three hundred miles long; US 101 is a slow road. If you have time, it would be a great trip from Gold Beach to Astoria.
I particularly like the area south of Newport, Yachats, Cape Perpetua, Devils Elbow State Park with the famous Heceta Head lighthouse. You can drive along that relatively deserted part of the coast and stop almost anywhere, there are lots of state parks, and get great stuff.
Weather on the Oregon Coast, except for August, is always a gamble. I've had days of rain even in August when it can go 60+ days without rain inland.
Good luck.
Eric