In Michigan if you have the Annual Passport you can dump free at any State Park that may be along your route.
Also, I've found that boondocking in the National Forests in Michigan (lower & upper) there is usually a dump station in the general area (behind party store, local gas station, county park, etc.).
The National Forest CG that I'm presently camping at has a dump station..., but no electricity.
2016 GM 2500HD 6.0L/4.10
2018 Jay Flight 24RBS
2002 GM 2500HD 6.0L/4:10 (retired)
2005 Jayco Eagle 278FBS (retired)
1999 Jayco Eagle 246FB (retired)
Reese HP Dual Cam (integrated sway control)