Garage dimensions?

I've seen many posts that mention that garagability (did I just make up a new word, or just misspell one?) was a key feature of TrailManors, leading many people to select TMs over competing TTs. I agree that I'd like to be able to keep a TT in my garage. My situation is a little different from many other prospective TM buyers. We're saving our pennies for several large projects, including expanding our garage, buying a suitable tow vehicle and buying a travel trailer, probably in that order.

Many of the recent posts have mentioned the size of an existing garage and asked if a particular TM model would fit in that garage. If we're going to build a garage first I'd just like to know what dimensions would make a TM fit comfortably into it. The model we're leaning toward is 3124KS, with A/C. To avoid saving pennies for an extended period we'll probably look for a used unit rather than a new one, so I don't yet know what model year it will be or if it will have a swing hitch.

Can anyone please suggest what minimum size garage would be best for a 3124KS? I've seen the stories of backing in until something on the TM collides with some part of the garage. With some forethought I'd like to avoid that parking maneuver.