We drove from Sparland IL (20 miles north of Peoria) to Lakewood, WA (20 miles south of Seattle) in 3.5 days. We traveled via I-90 and did very little sightseeing along the way as I had driven this route before. You can push it a bit more each day and do it in 3 days. We travel with a dog so have to stop more. About 1900 miles each way. Prepare for delays and detours in mountains due to construction and rock slides -- they happen.

It generally depends on where exactly from each city you're going and starting from, but it's about a 30 hour drive.

Driving distance is a little over 2,000 miles, so assuming you cover 500 miles a day, that's a four-day trip.