Yeah, don't go thru SF
On the Oregon side of the Columbia, there are some State Parks Fort Stevens is right on both the ocean and the Columbia River and it is a nice park, but my favorite is Cape Disappointment on the Washington side. It has two lighthouses to explore and an interpretive center, plus the ocean with lots of sand.
If your talking about going up the Columbia a way, either side has some great options. Columbia Hills (use to be Horse thief) and Maryhill would be your best bet. On the Oregon side I would recommend any of the parks and would probably be your best bet for waterfalls, There is a 30 mile scenic drive that is awesome.
