look, it is possible to have a blast if you put some effort into it. ANUSa runs plenty of social events, and many other clubs and societies run events of their own as well. dig around a bit and you'll find open-access events that will suit you.
That same paul guy sent me a message on Wikipedia (I work on the ANU Halls and College wikipedia pages quite a bit) 3 years ago with exactly the same content.
It's going to be a prefabricated modular construction, so my guess is that it'll be up quite quickly. Still you might want to make a few calls or emails to the uni to confirm
As long as you are prepared to walk away from the residential halls and colleges, yes. There are quite a number of outdoor places with wireless coverage, and all libraries will have them as well.
I do law, so if i'm free I can walk you through the law faculty and the law library. That said, I'm quite sure the faculties will be staffed, and someone there can provide a more 'official' tour.