I would seek out an organization for sewing enthusiast. Most of these members have all kinds of expertise and you will have one on one help. I do not know where you live but try the American Sewing Guild. They are a National organization and to the best of my knowledge they have a chapter in every state. Good Luck
You said that you wanted warmth from this coat. Please review the collar / neckline. When the wind blows your neck is wide open.
Thanks very much for your detailed answer! It helps a lot. I am slowly working through beginner books for sewing and learning what patterns are and how they are incorporated into sewing projects. It's very exciting but almost like a completely new world that I need to learn the ropes of... I will be posting more questions for you all as I get further along this (rather daunting) project!
I am going to be checking out all the resources you have recommended now.
TinyPliny, ask all the questions you have. Everyone here is very helpful and willing to share their knowledge.