You didn’t mention which version of Rhino you are using. Please always provide the output of the Rhino SystemInfo command when reporting an issue.
You should be able to use the Scaled to Fit option in the View and Output Scale.
I see that the preview is wrong and that it reports 100% as the scale, but the resulting PDF seems right.
-wim
There seems to be quite a few posts about various printer issues, and for some reason after reading your response to this one it popped into my head that maybe it would be a useful idea to include in the systeminfo report the current printer attached to the user’s computer and it’s driver information? just a thought.