I like the design, yours is a larger version of what I'm working towards.
The lean to portion interests me. I have an 18x30, and want to add 14' in the same fashion as your lean to. The tie in of the roof line and sharing the exterior wall of the main portion to be the interior wall of the lean to is the unknown as I work through my plan.
Will the lean to be sealed/ water tight at the connection/ roof line? That would be the key for my extension, I want to move my wood working equipment into the extension with a concrete floor.