The AirVPN and IVPN clients for Windows are pretty much leak free. And dead simple. Buy account, download client, install, and run.
And for Whonix, it's just download and install VirtualBox. And then download Whonix, import into VirtualBox, and run.
Whonix / VM:
* Figuring out which version of virtual box is appropriate for her setup. The download page is not at all noob-friendly and there is no big "click this button to download for this OS" button. What does windows host mean? Does that mean windows? What's an SDK? Do I need the extension pack?
* Figuring out which version of Whonix is appropriate for the same reason. Download securely without verification? Is that ok? What's a signing key? Open pgp? What if she downloads the wrong one? Will it fuck something up?
* Feeling comfortable employing a VM. She has never used a VM and would have no idea what was going on when a different OS appeared within her OS. This could be very unnerving because it seems incorrect. The idea of importing an image would be so foreign that she might not be able to figure out how to do it using the virtualbox interface.
* Trivial tasks on whonix. She wouldn't know how to do trivial things on Whonix because it is has a totally different UI than Mac or Windows. Most non-technical people memorize what they have to do to accomplish tasks without actually understanding what they are doing so they can't port that knowledge to another platform.
* Troubleshootong. She would not be able to use Google for help because she can't form the queries correctly to ask what she wants.
* Determining which VPN(s) to use and signing up. There are about 100 options and she has no way to evaluate the quality.
* Determining whether the VPN was set up correctly. Leak tests? Checking external IP? What's an IP?
* Understanding why certain things don't work anymore. Why can't she print documents anymore? Why are certain sites going to the Canadian page instead of the regular .com page? Why isn't Netflix working anymore? Why is she constantly dealing with captcha?
* Understanding why everything is so slow
She would quickly realize she is in over her head, get frustrated, and then feel embarrassed because she would have to call me for help with what you described as a "trivial task". She would probably just not do it to save herself from the embarrassment / "wasting my time".
That's what's so good about Tails. You just boot it, and have a secure Debian system with Tor. But there are some vulnerabilities. Especially because the Tor daemon and userland are not isolated.
It one point, I experimented with packing VirtualBox, a pfSense VPN gateway, and Whonix, in a LiveDVD. It required 8GB RAM, and took minutes to boot. But once it was up, it was quite snappy, because it was all in RAM.
Anyway, it would be cool if someone could pack all of that in an app.
And if you really haven't heard of Whonix, I find it hard to believe that you've looked seriously into privacy protection. But maybe I'm just biased.