You can still travel south on Corridor 19 via the Seven lakes club trails towards Province Lake into Wakefield to By-pass that section of RR track thats off limits. To be able to continue south from there, depends if the lakes are frozen. You can see the area in question by looking at this map. I for one am very disappointed in the closing of this trail, as I live right on corridor 22 just to the north of Lake Wentworth.
http://backwoodsgpstrails.com/SledMap/SledMap_J_E.html