Living in South Dakota, I have never considered making a cross country trek during the winter. Although I have had the occasion in December, January, and February to take the bike out for a quick spin on a day we call "a January thaw", that is about it for me.

As you have lived through, sub-zero temperatures is what I would be paranoid about. I have done a 50 mile ride when the temperature was +5 degrees, and although I had a snowmobile suit and all the equipment...was I glad to be done with that ride! I can't imaging doing hours of that.

IF El Nino holds up, which it appears to be doing here in the mid-west, it may be a doable year for your cross country trip. I will never forget driving near Green Bay WI one early March day, it was about 15 degrees out with snow piled up everywhere, but the roads were dry. Two BMW motorcycles with younger riders were heading south. After they passed me by, the sign attached to the license plate "Daytona or Bust!" I couldn't help but wish I was going with them