To answer my own question (and Dave Garwood, you may be interested), in
fact it's easy to print from Xywrite for Windows if you make a few
adjustments.
1. in C:\otvdm, edit otvdm.ini and remove the comment (;) at the start
of line 43, so that it reads:
EnumFontLimitation=1
This limits the number of fonts available to 16-bit programs, and avoids
error messages when there are too many for the program to manage.
2. Edit XyWin's XWSTART.INI (you can use any text editor) and change the
setting for UWF from 2 to 1. I don't have a manual, so I suppose UWF has
something to do with Use Windows Fonts. A setting of 0 turns off screen
fonts; I don't know what 1 and 2 mean. But I found a reference to this
setting here:
http://www.holmgren.org/XySearch/mail/msg18749.html
Again, I don't know what these settings do.
3. Now, whether you can print or not depends on the Windows printer
driver that you choose. Microsoft Print to PDF certainly works for
creating a PDF; so does BullZip PDF Printer. I found that the HP
Universal PCL5 driver won't print anything, and a PostScript driver that
I use with my HP LaserJet only produces an error. But the standard PCL6
driver for my LaserJet prints perfectly.