December/January are a good time to take that trip is fishing is on the agenda. North of San Francisco you've got the Russian river right off 101, further north the Eel, (there are a few smaller others), then the Smith just south of the Oregon Boarder.
Once you cross into Oregon (5 miles?) you hit the Windchuck, then the Chetco, and and hour and change north you're at the mouth of the Rogue river.
From there on up to Washington it's one coastal river after another, after another.
I'll get you the link to the Oregon Fish and Game web site, it lists damned near every body of water in the State, and what's going on at the moment. Info can be a bit dated, but I've found it to be quite accurate overall.
Just click on the zone you want to review and you're good to go.
Edit/edit: USGS river gage info is darned helpful in planning your trip. Weather forecast will tell you a lot, but the gage really tells you what's going on. Most rivers have one or more depending upon the length of the river. Here's the one for the Chetco: http://waterdata.usgs.gov/or/nwis/uv?14400000
Only thing 'wrong' with the Chetco's gage is it's located about 6.2 miles up from the mouth so the reading doesn't include what's coming into the lower river from the North Fork.