Did you try contacting the author(s) of the papers? In my experience, most authors are happy to hear about uses of their work (even if they are in a...
There are lots of tools out there that can do hillshading on available DEMs. QGIS is one option. A reasonable dataset for maps of the US is ETOPO2.
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Hello Maximillian and welcome to the guild. As for software I think try out all of the free ones first and get a general sense of what works for you....