Started at Portage Lake and finished at Pinckney Rec Area. My wife met me every 10 miles, which was much appreciated because it was a hot one. Ice bandana was clutch. Took a few small wrong turns and had to backtrack, and the Discovery Center around mile 20 was being renovated so I had to go around some construction. There's definitely some meat on the bone if someone wants to lower this time. Just be aware that the new trail sections on the Potawatomi that opened last Spring felt like they added some distance... I'd say it added a half mile or so compared to the old route.
I love this trail. Beautiful Great Lakes-style singletrack with a good mix of hills and terrain. The surface isn't the fastest (if it's wet it floods, if it's dry the horse trails are soft sand) but you can still flow if you have decent trail legs.