It's surprising the north-west is not more well known as a spectacular destination, if it's as good as you all are are saying.
Rather than doing San Fran to Portland by car, would it be worth flying to Boise and driving west then north once we hit the Pacific?
Scott,
As a general rule the entire west, outside of the desert found in Nevada/Eastern Oregon, and Southern Idaho is pretty epic and worth driving to see.
As for flying into Boise and driving north and west of there, I would say thats a relativly bad idea.
Your best best, in my humble opinion would look something like:
1) Fly into Denver, check the place out a bit.
2) From there drive West on to Hwy 70 until you hit Hwy 6 which leads you into Moab where Canyonlands and Arches are. This is epic country.
3) After, drive South on 6 and make your way over to the South Rim of the Grand Canyon as the North Rim will likely already be closed by then.
4) Continue south to Flagstaff where you come to your first decision. You can either continue South to the Phoneix area and have a look around, or head west over to Vegas. I've only been to Arizona a time or two so don't have any recommendations down that way.
5) Assuming you head over to Vegas, make sure to check out the Hoover Dam and spend at least a night on the strip. It should be experinced at least one for its sensory overload even if its not your cup of tea.
6) At this point, head West out to the LA area and spend as much time there seeing whatever gets your interest.
7) Once done there, head north on 101 going thru Santa Barbara and Solvang. Continue up thru Santa Maria onto San Louis Obsipo. Make sure to jump over to 1 and take the coastal rode up to Monterey....its a great drive.
Once you hit Monterey, so many things to do, but whatever you do don't miss 17 mile drive...its the nicest stretch of coastline on the whole trip IMO.
9) Continue up 1 till you hit San Franciso and there is a whole world of things to do there.
10) From there I'd continue on Hwy 1 all the way thru Bodega Bay and Fort Bragg, even though its a pretty remote stretch.
11) Eventually you'll hook on to hwy 101 that will take you all the way thru Oregon.
12) So many options here...you can jump off to go catch a flight in Portland or continue on up to Seattle.
Steps 7 thru 11 on this trip could be done in 5-6 days imo and still be able take in alot of the interesting sites along the way. But it could just as easily be stretched out to two weeks with plenty to do as well.
I can say this though, if you do nothing else out West, don't pass on the coastal trip, that is unless you easily tire of two lane winding roads.....