I don't know if anyone's tried this route, but there's been a tiny part at the back of my brain has been wondering if loading a custom demorecord file in, pausing playback, taking a load of screens from multiple angles and then feeding them to a photogrammetry program like Autodesk 123D (
http://www.123dapp.com/catch) might be a way of getting geometry and textures out in a usable form?
And regarding shadowplay, yes, it should be pretty straightforward to disable, open up "nVidia GeForce Experience" (horrible names R us (tm)), Click the Shadowplay button at the top right of the wondow, and click the big power button.
If it's already off, then nVidia must be doing something funky, so uninstalling GeForce Experience, and maybe rolling back to an old, OLD version of the drivers could be required.