Closest spots I know of is Buck lake/HHA/bruderhiem? all about an hour. Those are the closest spots I've been to.
Probably some closer, I just don't know them.
Grew up right around Coal Lake East of Millet - used to ride on a bunch of Crown land on the North end of the lake (both East and West sides), and also at SouthEast corner of the lake but that was 20 years ago. Not sure what's there anymore or if it's now all private land.
If you have time, take a drive to see what's there or see if you can track down more info on the area. Might be easier to explore the area on a sled this winter.
Head Straight South from Beaumont until you hit 616 - travel East about 3 or 4 miles until you drop into the Coulee.