What do your local building codes say about this? How would you access that space? Can you afford the much larger expenditure? A garage is already easily a 40K expenditure, and adding actual habitable space above it, another 40-60K, depending on whether or not you do the plumbing to create a "suite".

and these frogs (family rooms over garage) are hard to heat
and cool. go to hvac forum & search for posts about frogs.

nice house...can we see the lake view?

The picture is not of our house, but of a nearby house. It is not big, but the guy did an AWESOME remodel--all top-of-the-line materials inside.

We went to his open house and while we appreciated the extra space the room over the garage afforded, it's kind of awkward--second floor, no bathroom. The link is here, if you want to check out the lakefront view.

I'm toying with all the possibilities before we start any construction on our home, since we are residing and I hate to get it all done and be thinking "Ah--we should have done this or that." Thanks for your feedback.

Here is a link that might be useful: Lakefront Listing

I'm not sure how a link to a house that isn't even yours is supposed to help. Unless you are saying you bought the exact same house sans garage addition?

To me the second story over the garage looks completely out of place. It screams afterthought.

Do people in your are demand these awkward spaces? I'm not sure how you mean it will help resale.

If you have no use for such an addition, leave it to the next buyer.

(Personally, I like it as it suits our needs--apartment for an adult child, separate office for our businesses, future rental suite, guest apartment.)

Spray foam insulation eliminates the heating/cooling problem. But you will likely need a separate HVAC system.