Despite his tragic and sensationalized death, this evening I was able to conduct a séance with Mr. Scotts via AOL Instant Messenger. He confirmed that the text of his game should indeed be legible and he suspected bugs were afoot. I explained to him the many, many different operating systems that have proliferated since his demise, and he suggested I test his game on some of them. He was particularly insistent on testing in OS/2, as he believed it to be the operating system of the future.
I quickly verified several OSes, including Windows 10 running DOSBox, Vista and XP (where the program runs natively), and in a virtual machine running FreeDOS. All were successful. I also tested the game using an old laptop with Ubuntu 14.04 and DOSBox 0.74, and it runs correctly there, too.
I suspect this might be some sort of weird DOSBox issue with non-Windows 64-bit systems (and maybe just 64-bit Linux). I talked with JTN about it and suggested to maybe run the Windows version of DOSBox via Wine. It was confirmed that Infinite Adventure worked correctly in this manner, using the DOSBox0.74-3-win32-installer.exe file.
I thanked JTN, and went to tell Mr. Scotts about my results and to thank him as well. But by then, he had set his status to Away, leaving only his parting message: “Happy INFINITE ADVENTURING!”