Well, Google oauth is a totally separate thing from G+.
Anyway, I tried setting up a server on my local machine to test stuff, and honestly I lost the will to live about an hour in. I really, really don't like Apache or PHP. I think another way would be to just backup the database (through the control panel), and then turn on features we want in "production" and see how it goes. The FriendsOfFlarum would be my first choice for a new extension, as that seems the most useful.
Another thing we could do is add a manifest to the root of the forum, which is a simple JSON file that lets you specify how the site is displayed. This way if you've added the site to your home screen then you can make it appear like a normal app, rather than running in a web browser. This is a simple thing to do.