I think the stretch to Watsonville is too long particularly coming off of a fairly long drive to Eugene from Bellevue and the fact the mountain drive is in that stretch. I do think getting to Eugene from Bellevue is fine although somewhat long. The advantage of going to Eugene is that you will be going over the pass at the Siskiyou's at the end of the morning depending on what time you start since it is about a 3 hour drive to the start of the pass. I would highly recommend breaking the trip up from Eugene to Watsonville in Redding. After the mountain drive ends right after Lake Shasta and you roll into Redding I guarantee you'll be ready to stop. It's a five hour drive from Eugene (and really I count 5.5 to 6 with stops for meals, etc.

And to answer your question-I do think it's pushing it a bit to get to Ashland in one stretch although I know drivers who do it.

Also, just a reminder about timing your Bellevue around the traffic through Tacoma and Portland-those areas can have nightmare traffic at times~I'm sure you know that!

Oh I also wanted to post this webcam link for the Oregon stretches of I-5. Always good to check on webcam as you get closer :)

I-5 at Siskiyou Summit, Oregon Road and Traffic Cam

There are similar ones for CA once you decide what route you are taking.

I live in Eugene. Have only driven this route once- in January. We drove as far as Santa Nella the first day. It was pretty doable with 2 of us driving.

Truthfully jpie I am not very familiar with Bellevue or Tacoma traffic. I've not lived here long and don't like to drive. Ironic, isn't it, that I'm planning this one? I will heed your advice with gratitude. I am so thankful for the input I've received here and feel so much more confident of the drive. Thank you ALL!

Well, since you will be driving from Bellevue down you will probably be taking the I-405 south down to where it rejoins I-5 south near SeaTac Airport. And if you leave in the morning, you should be going "against traffic" mostly, so you should be fine. And sunburn1944 makes a good point that you might be comfortable driving a bit longer if you have 2 drivers. But in the winter I still tend to shorten my driving days.