This guide to the Midland to Mackinac Trail was written in 2018 from a once-through hike. The guide includes approximate mileages at landmarks/turns, water access points, potable water (usually seasonal), both formal and suggested camping spots, and certain other facilities.
The trail, estimated 210-215 miles long, is divided into 17 segments, and traced across 30 maps which use USGS topo maps as the base. As yet, there is no GPS line for this trail. Placement of the trail on the maps is based on DNR info and personal observation.
It is bound to be inaccurate in certain places. That said, there is no other document available with as much information as this contains. If you are planning to hike the M2M, this guide will be a valuable resource.