I wouldn’t call the following “flow trails”, but there are some really good rides fairly near you: The Pota (Potawatomi) (in the Pinckney RA), Fort Custer RA, Brighton RA, Pontiac Lake, Novi Tree Farm, Milford Trail, and Maybury. All these trails are within an hour of Lansing. You can read about all of them here on Singletracks. Some I have ridden. Some are on my wish list.
DTE is close to you and and a lot of fun. Almost every turn is banked, but you have to earn your speed because there is not a lot of elevation. There is enough, I really liked it. I will also second the Brown County State Park vote. It’s not in your backyard but a good weekend trip.
The top of your state (Copper Harbor) has some world class flow. Haven’t been to Brown County since they’ve added flow but the trails are amazing. Seems like little flow sections are popping up everywhere these days.