As far as I have heard, Torrance Barrens is open for camping (word of mouth in Muskoka).  I don’t think there is any way to contact the park for information and the only true way to find out is to go there.  They do have a facebook page, but it doesn’t look like it’s monitored often.  I would send them a message there and see if someone may reply, or post on the page and see if someone has been there more recently and could confirm.   Best of luck in your search.   https://www.facebook.com/TorranceBarrens/

We were just up there and there are no camping signs all over the place around the parking lots which have developed. Having folks in there with fires etc. would really ruin the Dark Sky Preserve wouldn\’t it?