I did this road trip years ago with my spouse and we ended up moving to the PNW soon after. I agree with the others, take I-5 and stop along the way. Try not to speed, you can drive a little over but not like in LA/Southern California. Stay on right and if you need to pass, use the left lane. You should definitely stop in Portland if you have time, lots to see and do. I love eating at PDX Sliders and Nong’s. You might even want to take an overnight break there. You can take a quick detour to the Columbia River Gorge and do a short waterfall hike/visit Multnomah Falls for a quick photoOp. There are several rest stops along I-5 in WA and OR, sleeping in your car overnight is permitted —you can’t stay more than one night. Restrooms are fairly clean and some offer free coffee! While in Seattle, you can get a decent city hike / stroll if you go to the Arboretum. It’s not raining as much this month as years past. It’s been a fairly warm fall and we have had some cold night, layers and sleeping bags should help. Try to keep your belongings out of sight or take them with you if you plan to park and leave your car, break-ins are common everywhere, even at trailheads. Best of luck, have fun, make some great memories, and welcome to the PNW.