Do NOT build your garage at the back of your property. Build it about 50 feet forward of such (taking into account easements and such).

Why? It's much cheaper and easier to extend out the back of your current garage when you need to than it is to move the front forward (Re: doors, concrete, lighting, etc.).

Yea 40 is the number I think I will go with, I have a meeting with the building inspector tomorrow, just trying to get some rough sizes together.

No less than 40'. My garage is 40 deep and my 28 with a swim platform on an aluminum I beam leaves me with a foot in front and about 4 feet behind with the drives down to walk around.