Seeing your trail report reminded me to post our recent experience.
As a former board member of both GLFWDA and UFWDA, I always am overly cautious about new places to play. The big magnets on my door advertise my affiliation with GLFWDA too. Last year some of my club mates ventured into the state forest roads near Evart, MI. They found a designated scramble area north of Evart (If you get your hands on the "Evart Block" map from DNR it is at marker 6720 in the NW quadrant of the map) called "Sugar Bowl" that had nice hill climbs, including some rocky ones. Not trusting the very vague signs, two of us contacted two different DNR offices for clarification. Both said "have fun, designated scramble area".
Last weekend we were in the same area, and a DNR officer followed us into the bowl. As we started to pull out our lunches, he asked that we all gather round - he wanted all of us to hear it first-hand that we were out of bounds. It is a designated scramble area for ATV and MX, but not for 4x4. The signs were missing or not clear, he knew it, and just made it an informational stop with no tickets. Nice guy, very professional - my 14yr old son was driving (learner's permit), so his first encounter with law enforcement behind the wheel - but still an uncomfortable stop. The area has been closed to 4x4 under a Director's Order dated 2000 or something like that. Not sure how 2 DNR offices flubbed that one.
We followed up with DNR Parks and Rec staff, they will be heading to the area soon to get the signs installed/replaced as necessary, but until they do, please enjoy the view from the top edge of the bowl, or consider walking in with your lunch.