I think you're screwed. The reason I say that bluntly is because anyone that thinks they can gear up for potential -40F temps on the advice of others is, imho, simply wrong and I say that having had a lot of experience cycling to -30F and a bit of experience at -40F. Steve0257 is right on. I promise you that no matter what advice you get and follow you'll find problems you didn't expect like a bike rack bolt that becomes loose in the cold temps and falls off leaving you unable to continue. Simply packing a bike for camping at -20F is a challenge that requires experience, not advice. I do wish you the best of luck but I'm also quite sure you're going to suffer and probably fail (again...hope I'm wrong) if you attempt biking and camping at -40F without some real experience before you go.