Layering your clothing in and outside your sleeping bag; heat packs or water bladders filled with hot water at your feet or midisection in the sleeping bag. Make sure the caps seal well or enclose in ziplock bags;
A candle in a can can warm a tent a bit; a vapor barrier can add degrees of warmth to your bag; a breathable bivy over your sleeping bag adds degrees of warmth; supposedly 40+% of body heaat is lost from the head and neck- use a balaclava to cover both areas. A thick pad under you is most important.
Campgrounds won't be as crowded in cold weather.
Enjoy the tour and your new status.