The set, of course, was printed on poster stock, with each subject measuring 9 3/4" x 18 1/2". The stock is the type used by Topps in their standalone poster issues and not the cheap, recycled stock they used for their inserts.
The wrapper can be readily found these days:
You can even find a box with a little hunting:
The box bottom has the ubiquitous commodity code, which started showing up in earnest by late 1966 on most Topps products:
The posters, designed of course to be hung on walls, are harder to find than the wrappers but they are out there. A full set was recently offered on eBay and I thought it would be nice to show a visual checklist as so many of the larger-sized Topps sets are hard to scan or otherwise reproduce.
That artwork is insanely well done for a set that retailed for $1.20 a box!
There is a great display of the Sing-Sing artwork (by Wally Wood) over at the Artwork Archive, go check the site out as it's loaded with goodies, but in the meantime:
There is some commonality of themes with the 1965 Silly Stickers, which had 55 subjects, a good number of which also had a travel related gag, but Chris Benjamin's take that the posters borrowed artwork from the stickers is incorrect:
You can see though that the gimmick on the stickers was the use of a tiny word to change the meaning of the gag.
Ya gotta hand it to Topps, they really would go all out for their posters and similarly sized sets.