I rode in the 40's the other day on the BRP at sunset(got cold quick).
I wear my j.r leather pants and boots with long sleeved and legged thermals/long johns.
Insulated socks. Winter bib top coveralls over leathers.
A winter nylon armored Joe Rocket jacket/not ventilated.
A snowmobile ninja style hoodie that covers your neck.
A quiet rider that encloses the bottom opening of the helmet.
Most important, heated gloves! Good quality too, like Gerbings, ones that heat the back of the hand and fingers too. Otherwise they're just like heated grips, because the only heat is the palm of your hand an insides of your fingers.
Meanwhile, the back of your hands and fingers are taking all the cold wind.
I started to get cold the other day, until I plugged my gloves in.
Warmed up almost instantly.
If it got much colder or I was going to ride for more than an hour or 2, I'de definately buy heated insoles(or socks if you prefer) and a heated vest for under any jacket.
The heated gloves, quiet rider, snowmobile hoodie, and some insulated coveralls(that fit easily over gear) are the easiet ways to stay warm.