Thanks Head Hunter. I always thought it was DNR, since you approach via DNR land. I first fished Lake Ten back in the 80's before there was any development. You could drive right to the trailhead and park. It was popular at the time. I could get off work, grab a can of worms and get to the lake in less than an hour.
I saw a lot of people at the lake when I was there last year. I doubt if they were all Keith's family. I would sure recommend trying to contact him for permission before visiting the lake!