Ok, I'm pretty sure cawf 4.10 is the last version of cawf. It's from 1996. The minix version I was playing with earlier is either 4.8 or 4.9.
(groff released in '97, pretty much made cawf pointless)
It was an easy port to RISC OS. I have a little bit of packaging to do yet but it's basically done.
Unfortunately it still can't deal with mandoc or mdoc manpages.
Spent most of the day hacking around with RISC OS cawf.
The old port from the 26-bit era had an "acorn" output device. Turns out this generates output that First Word Plus, an equally ancient RISC OS word processor, can read. Modern Ovation can read this, as can Writer+ (but not quite as well).
RISC OS printer drivers from the era might have understood FWP files directly, I'm not sure.
:( no props at all to ftp.funet.fi for having the source for epson2ps and letting us look at the directory but not letting us actually grab the files. ):