For me and I speak only for myself the perfect format for a physical copy of a role-playing adventure is the zine. I do not mean a standard size adventure shrunk to zine size. I mean an adventure that has been formatted specifically for print as a zine. After using such adventures at the table, I find the format far more practical and enjoyable.
There are several factors that contribute to this. First, of course, is the physical size. It takes up less room behind the GM screen, and I can hold it open comfortably in one hand if I wish to stand up and walk around. Maximum GMing convenience.
Font choice is critical. A proper zine adventure needs to be of a readable typeface and size to facilitate ease of use. I don't need anything fancy. I just want to be able to read it quickly and without squinting. This, I'm afraid, is an all too frequently undervalued aspect of adventure (and rule book) publishing. Save the ornate fonts for handouts (torn pages from tomes, letters from the regent, secret notes passed by spies, et cetera).
Each room description (or other location description) ought to start a new page no searching the page to see where descriptions begin. The only time a page should contain more than one room description is if those rooms are empty or otherwise identical. Any space not filled with text or illustration can be used by the GM for note-taking.
Each map ought to be given its own page. Larger maps ought to be printed on a separate sheet, folded, and inserted in the centerfold. (If there is more than one map on a single page in a zine, the maps are too small.)
If you've never run an adventure in zine format, I encourage you to try it. Some things, like rules, only prove themselves through use. (I recommend "The Sanctum of the Snail" included in Crepuscular #1.)