Nothing fancy , just optimum sized (subjective, naturally ) foam box proportions ... 60 sq. feet floor space, 60” tall inside . You could do any inner framing you like … Just don’t make it too heavy …
Simple as it is , it doesn’t have to look it , just a nice paint job does wonders to dress up the simplest cracker box …
![Wink ;)](./images/smilies/econ_wink.gif)
And it should be garageable ...
For your consideration …