For all the longer trips we (me and Mrs TimE) do I budget $1/k. That figure takes account of everything, fuel, food, grog, entertainment. eating out, park fees etc, and a contingency for R&M.
On our 17,000k trip this year I reckon I got close to spending the $17k. This included a new long range tank in Darwin (the old one split) and new shocks in AS.
If there are no big repairs costs I figure I've come out ahead :)
For a Google Earth view of my travels try this link
https://personal.filesanywhere.com/f...8c606073aa71a1