FWIW what you describe has been my specialty. I'm a hands on builder and I love to think my way through the difficulties before you. Working within and around the existing structure is a very satisfying challenge. I lived in FL untill last year and as you may know FL has if not the most then the second to most stringent codes and inspection program in the country and I always passed my inspections, I only state this as this is the basis of my perspective. Here in TN you can get away with murder or close to it when comes to the building practices and that may very well be true where you are, I don't know.

My advise is to think, think, and rethink before every decision.

Scott