If you want to stay on the coast then I agree with what everyone else has said regarding direction. Not sure, but it sounds like you're planning on going soon, which would be good. The weather in Oregon will be deteriorating before too long, and going north to south will get you out of there and down to California where fall is usually beautiful on the coast. IMO September is the perfect time to start the coast due to the lighter traffic after Labor Day and the weather is usually great.
Another option would be riding up 395 and eventually taking Sierra/Cascades or Lewis and Clark, or some other route over to Portland. It'll soon be too late in the year for that though. Depending on when you leave, it could be pretty cold by the time you get to Oregon, and east of the Cascades is colder than the west side.
On the wheels, if you're planning on being heavily loaded, you might opt for the cassette over the freewheel just due to the drive-side bearing positioning. I have a freewheel now and usually have to replace my axle at the end of a tour because it ends up bent (one of these days I'm switching back to a cassette). If you're going light it probably isn't an issue.