So there were a few things
1) the templates for the various project types so you can create new ones.
C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\Common7\IDE\ProjectTemplates and
C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\Common7\IDE\ItemTemplates
2) there were also some private assemblies that had to be moved from 2015 over (C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\Common7\IDE\PrivateAssemblies)
the important thing to keep in mind is that pathing for 2017 is new compared to previous versions of VS and some of the folders aren't int he same spots
i got it so you could create a new project but it tanked building so it might simply not work...i work with the custom parts mostly so I don't mess much with crm customization, not yet anyway.