Lanefan's suggestion of decreasing the font is a plain good idea. You can easily get away with a 9 font size if you keep the leading (vertical space) even just 2 pts. higher. So, font size 9, leading 11 is very readable. Leading 12, moreso if you're really worried about aging eyes. Also, you can play with the horizontal scalee, 95% is barely noticeable, 90% saves a good amount of space and is still very readable/barely noticed. As long as it's uniform throughout, you can make it whatever you want, though I think things start looking distorted around 85%, get to "squeezed" around 80% and damned near unreadable by 75.
I do layout for a regional magazine and the publisher's recurring fear was the eyesight of our middling-to-aging readership (who are the bulk of our subscribers receiving physical magazines.Most everyone else just picks it up in the bars or reads stuff online/from the website nowadays). We did a complete redesign a few year back. Copy text was set 9 pt., 11 leading, 90% across the board. Not a single complaint or comment about it being "difficulty to read." So, I'm speaking from direct experience.
Even just doing it for the boxed text or just doing it for the monster stats, you'll save a ton of room.