To answer my own question, in case it helps someone else, I changed Virtual Machine > Network Adapter to Bridged instead of NAT (which I think was the default -- at least I don't remember selecting it).
When I restarted the VM there was no difference, but I restarted it again and clicked Virtual Machine > Install Virtual Printer (which didn't produce any visible results) and for some reason this time it worked.
Worked perfectly. Exactly the right answer. Amazingly simple!