I spun thru Spider Lake a 1/2 dozen times this summer. You'll see lots of ATV's. Rarely, if ever, have I seen another Jeep in there.
It's basically a nice ride thru the woods. Nothing serious. Most of the trails you could do in two wheel drive. There are a few nice hills towards the southern part of the trail system. It was really pretty in there this fall when the leaves were changing.
If you want to actually "wheel", you have to go to Gilbert. Spider lake is literally twenty minutes from my cabin, yet, I rarely go there.
With regards to it closing, I heard that this spring too. I have no idea, but it was open all summer.