I am planning 4 nights in the Alsace, France Germany area visiting Xmas markets in late Nov and early Dec. I would love readers opinions of favorite markets and recommendation of lodging. I am flying into Frankfurt and comfortable using train and bus transportation. Would you suggest staying in 1 town and traveling daily to a different market. Or would you divide your time between 2 markets, such as Strasbourg and Colmar. I plan to then go on to Freiburg and then Basel. Thank you in advance for your advice.

I would divide just four nights between two places -- one in France and one in Germany. For France, I would recommend Strasbourg and for Germany it's up to you.

It is important to book accommodations for that period as quickly as possible.

Some will probably disagree but, when you think of the big names on French side, ie Strasbourg Colmar Kayserberg and Riquewihr, it is a bit always the same stuff.
So focusing on Strasbourg should be enough. You will find there several Xmas markets with slightly different atmosphere. Strasbourg over Colmar because it is a more convenient hub to go to Germany. Freiburg is a day trip (could be a very long day if you want to include Ravennaschlucht. For something different, you could also check Baden Baden.