Wengier Wu was right that I was getting Prof. Mendelson's older DOSbox-X-App from this page.
Under Catalina, I have found his DosBox much more immediately usable than the 83.8 version of Dosbox for Mac, likely because it is geared directly toward a word processor setup.
But I haven't figured out how to do clipboard transfers in Dosbox--can someone tell me?
--------------------
Some secondary info:
Prof. Mendelson's app automatically creates a DosBoxDisk folder (like VDosDIsk). It may have also prompted me for a little more setup; I've forgotten. But now when I open it I immediately get a C: prompt. Meanwhile, 83.8 gives me Z: and wants me to mount the C: drive each time.
With the Mendelson version, all I had to do was copy my XY folder into DosBoxDisk, CD to the XY directory and run editor.exe. All the paths in my startup.int and settings.dfl were immediately found, while 83.8 is getting error messages and beeps. Default paths in Startup.int were specified as C:\Vdosdisk\XY\. Under 83.8, I tried changing them simply to C:, since I had mounted XY as the C: drive, but I'm still getting some error beeps (even though beep is set to off in Settings.DFL).
The 83.8 Dosbox has considerably more extensive Mac menus, but even in the configuration settings I couldn't find a way to make the cursor stop rapid blinking. (Unchecked the blinker under Video, but no result.) The window is also smaller and lower resolution ("original" in the 83.8 DosBox configuration settings), though the fullscreen window is sharp. In Prof. Mendelson's app I can pull down the bottom edge of the window for a 50-line window, lovely.
I probably just need elementary instructions to get 83.8 configured and retaining the correct settings, but if I can get the Clipboard working under Prof. Mendelson's app that would also do the job.
Again, thanks to all who have worked on this, and for any advice.
Jon Pareles