The Outback Trail tour is the least jarring of their tours. I have some neck issues but I found this tour doable and had no problems. A woman in her 70s seemed a bit uncomfortable as most of the tour is on dirt roads.
Our guide, Joe, was perfect. Friendly, informative, good sense of humor, and he didn't get preachy about the vortexes and new age stuff. Just the facts.
Take the 9am tour if its forecast to be hot.
A nice 2 hours in some very beautiful country.