That would be a very long trip going WEST from Olympic Peninsula to Michigan.
I would go east and take the Port Townsend Ferry to Whidbey Island. Take WA 20 across the North Cascades. There is some nice Forest Service campgrounds.
Stop off at Grand Coulee for the evening laser show on the dam.
Continue east and pick up US 2 near Spokane and take it all the way home. Great highway most of the way.
Bud
USAF Retired
Pace Arrow
2003 Chev Ice Road Tracker