Comment 14 for bug 20330

Your summary of my situation is essentially correct and those two bugs (later than mine) cover most of my issues.

The remaining issue NOT covered is that I don't know how to get the networked printer to show up in the hp-toolbox frontend. This is useful because it (the frontend) shows supply levels and other detailed info on the printer.

As I understand it you need to use the uri like

hp:/net/HP_LaserJet_1200?ip=192.168.0.150

when installing the printer in order that hp-toolbox can see it.
I don't know how to do this. gnome print manager will not allow an hp:/ network address and the cups interface seems locked down for security reasons so I can't use the recipe for this situation described on the hplip webpage.