Ask someone locally. There is a lot more information needed and few people have the time to play 20 questions. Talk to a few local builders that can show up and see what you are talking about..

100-150K.

What would be an estimated cost of that project?

Between $10,000 (if you do everything yourself) and $200,000.

You’ve checked with your municipality about code set backs?

^^^ In my neighborhood all garages must be set back a minimum of 15' from the front of the house or 25' from the property line so what you're proposing would not be allowed here.