Personally, I don't understand why people don't use their garages. Just fit one of those automatic doors on the front and it becomes a breeze to drive in and out of. Your car stays cleaner for longer, it is not boiling hot in summer and it isn't freezing cold in the mornings during winter.
My suggestion would be to extend the garage forward - keep space for a car but add your office at the back.
Personally, I don't understand why people don't use their garages. Just fit one of those automatic doors on the front and it becomes a breeze to drive in and out of. Your car stays cleaner for longer, it is not boiling hot in summer and it isn't freezing cold in the mornings during winter.
My suggestion would be to extend the garage forward - keep space for a car but add your office at the back.