Grayling has roads that are worse then some trails. I was up a couple years back looking at land and we found places that drug the skid plates that were mapped as roads.
if you head north out of town up old 27 you will find route 612 in Frederic. if you go west you will find the entrance to the 9 mile truck route & 29 mile quad trails. if you go east out of Frederic then you will find the Tank trails out about 5-6 miles down 612. theres all kinds of access roads around the missle range so watch out for signs that say Keep out and live artillary.