Hi, and Welcome to the Great American RoadTrip Forum.

You're looking at roughly 2500 miles, or five full days on the road... four and a half if you were really pushing it. To meet your requirements of going through west OR and NAPA, you may not be able to meet your goal of six hour every day. (If you got the times from an online mapping program be sure to add at least 20%. Remember they never see congestion or construction, do not need to stop for a red light and travel at or above the speed limit all the time. Neither do they need to fuel up, eat or go to the bathroom.)

We don't actually do 'musts' on this forum. That all depends on you and your sister's interests and tastes. One person's must see is another's must pass by. If you'd like to share a little more of your interests and the goal of the trip, I am sure someone will come up with some suggestions to suit your individual needs.

Lifey