I set up DOS printing from within a VM machine with Windows ME loaded for Allen Merrill. Here are the steps I took.
1 – Download the AWESOME dos drivers made available here.
2 – Move the downloaded executable “wp51hplj.exe” to the WP folder.
3 – Double click it to extract the contents to the current folder.
4 – I couldn’t figure out how to change the default printer that is selected within WP for dos. It kept defaulting back to LaserJetIIIP for me. So, my solution was to rename the file to match the name of the printer driver that would always come up as the default when I went into the WP printer options.
Go to this columbia.edu page for full instructions on how to install the print driver for WP for Dos 5.1+ that you have downloaded.
Based on info from this site, you may need to use the built-in HP Laserjet6L PCL driver.

This is the Printer settings page for WP 5.1. For me the printer would always default to HP LaserJet IIIP. From here hit "s" and it will take you to the next screen.

Here we see the actual name of the HP LaserJet IIIP print driver -> "HPLASIII.PRS".

We see here that the file name for the downloaded HP Dos printer driver is HL12SEPC.PRS


Mine would always default to HP LaserJet IIIP even after I had selected the new 1200 laserjet driver.

Rename the HPLASIII.PRS file to HPLASIII.old

Rename the new HL12SEPC.PRS file..

to HPLASIII.PRS. Now it will show that you are using the HP LaserJet IIIP printer, but you are actually using the new print driver for the HL12SEPC.PRS