Seems to be the case that there is some issue with the Gutenprint drivers. Well done Kirk.Anyway it looks like the CUPS problem is something with Gutenprint.
I downloaded a ppd drive for my HP OfficejetG85 (hpijs/foomatic) from the openprinting.org website as you suggested. Also copied the hpijs file from /usr/bin in Puppy 2.17.1 and copied that to the same location in Beta 2.
So, copy the ppd file to /usr/share/cups/model and then run the CUPS setup from localhost:631. The new ppd will now be listed in the driver selection window.
Bingo - it worked. Not as good quality as the Gutenprint driver though, but OK as a temporary work-around. Better than nothing until the Gutenprint driver issue can be resolved.
I'll do a spot of research about Gutenprint over the weekend and see what gives.