Im sure this has been discussed elsewhere, but I know these sweat and such in swing temps...
is there a fast or affordable way to insulated them? If you are going thru the trouble to build a roof overhead, etc...
I have a 20 footer out back next to the garage. In 5 yrs, i've yet to notice any sweating problems, they are vented with storm proof vents. For the first 2 1/2 yrs, it was full of antique furniture and other household goods, they were fine.
I set it parallel to the garage, exactly 20 ft away. Eventually, I plan to put up a pole barn (just a roof on poles, open) from the garage, across over the container, and about 10 ft past the container. We painted the whole thing gray, the top white, but i'm thinking of painting the front and sides to match the garage. It still gets hot in the summer, the roof over it should reduce that significantly.
For setting, I used the 4" thick solid cinder blocks at each corner, with pieces of 5/4 treated decking as shims and spacers. It's settled some, I need to re-adjust it. There's about 6" or 7" of air space underneath.
Don't forget, these things have wood floors in them. If you get too much moisture underneath, it will rot out from underneath over time, or will bring termites to it.