Sounds like a great trip
I'd suggest a mobile phone that has good coverage in those remote areas (Telstra Next G worked well for me when I was out there), just in case you need to give accommodation a call to rearrange things or chase up the fuel, amend flight plans, cancel SAR etc.
As has already been suggested, take another pilot you actually know as opposed to a complete stranger. You don't want to find out on the first leg they are a complete tool in the aircraft regardless of how nice they sounded on the phone or when you met up to plan it all.
The Cessna 200 series suggestion and Night VFR rating were good idea's too.
And of course - a camera with spare batteries, spare memory card.
Most of all - have fun and keep an eye on the weather.