We stayed in a swag-tent (which I was initially skeptical about booking as I didn't know what to expect). These are permanent canvas structures, built one step up off the ground. Even though there was only two of us, we chose to book the quad-tent as it has two tepee-shaped tents with a practical covered timber deck in between with a small table/chairs, small fridge, sink, kitchen bench/shelves, electric lighting and a powerpoint (to recharge camera batteries, phones, etc). The tent itself had two comfortable single beds in each tent (bring your own linen or rent it), electric lighting, heaps of ventilation that you can open/close and insect screens.
For those that camp, or book the swag-tents without the deck, or stay in the railway carriages, there is a large, covered, central, communal meeting/cooking area with pots/pans, large tables and a large fridge.
The pool area is beautiful, large and clean with a real resort feel.
The wildlife is a highlight - there are kangaroos hopping around (or just lazing around) the grounds everywhere. There are also many birds that visit the site, along with parrots drinking at the windmill and kookaburras to wake you up in the morning.
We did a couple of the shorter walking tracks that led to amazing views overlooking the area, but for the fitter people there are many other longer tracks that would be spectacular to do at sunrise/sunset.
Our reason for visiting was for the famous Opera in the Outback - held out in the open, under the stars. I've never been to an opera, I don't do opera, but this was an AMAZING experience and I plan to go back for this every year!
A tour of the Undara Lava Tubes is a must - they are breathtaking!