what's the best route to go from San Francisco, California to Seattle Washington

80 to the 505 to the 5 all the way up.
You'll start to climb above Redding and then it's up and down grades through Shasta up to Yreka. The grade going down the Siskiyous is what you should pay attention to. Watch your gear selection and your speed going down. Many a brake is smoking by the time you get Ashland scales. Watch for traffic at the bend around Portland and the bridge over the Columbia river. After that it is not bad until you get to the crazy traffic in Seattle.

 

What he said !

 

Oh, and remember, OR is not a IFTA state. So therefore make sure you dot the "i"s and cross the "t"s because as it has been oft repeated here: OR considers drivers as "rolling ATM's". Not the good people of OR, but rather their state gov.

 

I usually get off at Weed and jump onto 97 to 58 into Eugene. A few less hills. This is an old habit when 97 was less crowded and the weather USED TO BE a lot better in the winter.

 

I just checked that route. How is it on time going to Eugene?

 

Depending on weight it is an hour-2 hours quicker. There are a few small hills but nothing like the Siskiyous or Grants Pass etc. The biggest grade is favourable dropping off Willamette Pass. There is more truck traffic on there now. The weather used to be a lot colder and drier across there. Lots of times I-5 would be shut down or have chain law and it would be dry and dusty across there. About 15 years ago it started getting warmer and wetter across there with more snow.

Give it a try next trip and let us know what you think.

I'll admit I'm prejudiced towards getting off the interstate and on 2 lane roads.

 

I took that route today.
Thanks Native Dancer, great tip and some beautiful country to drive through.