At the minute, yes that is the plan. For the whole trip (Route 66 plus the route across the north and the Pacific Coast) I have based the estimates on 4 weeks, although in reality can have an extra week if needed as a contingency. Ideally 2 weeks for Chicago - Seattle - San Francisco/LA, then 2 weeks for Route 66 itself.
For the first section between Chicago - Seattle - San Fran I will be the only driver, so will factor in the additional time for rest stops.
As a guide, I came up with the following:
Day 1 Chicago - Milwaukee. Milwaukee - Green Bay
Day 2 Green Bay - Minneapolis
Day 3 Minneapolis - Sioux Falls
Day 4 Sioux Falls - Mt. Rushmore
Day 5/6 Mt. Rushmore to Yellowstone. I'll aim to stop somewhere overnight but to be decided.
Day 7/8 Yellowstone - Washington State (again a stopover)
Day 9 Washington State - Seattle
Day 10 Ideally drive from Seattle using 101 around the Olympic National Park. Overnight stay in the Astoria area
Day 11 Astoria - Portland
Days 12-14 Portland - ?
Aiming to keep the driving to under 400 miles per day, with the longest being Sioux Falls - Rushmore. The section between Portland and San Francisco or LA is TBD as can add an extra few days onto this section if needed, and this I hope will also cover any delays/stops on route.