Cache WordPress for offline use

You could use Teleport or some other crawler to create a “proper” offline version of the website. However, if your client would want to showcase posting something or some other functionality that requires database interaction, then you’re far better off using a local installation on XAMPP or alternatives of it (enable Apache and MySQL to run as Windows services and make sure all the links in the local database point to the local URL and you should be just fine).

Also, if she has access to even a shred of internet connectivity, just make sure she has TeamViewer installed so you could offer real-time assistance in case of emergency.