all whell drive treks????

hello,
l am joining this year due to the travelling my wife Mary and I (Anton) will be doing in the next few years. we are starting to begin the "older mature years", BUT, we find most here is for 4WD only. We have a Subaru outback and just love it. It is 3 years old, top of the line model, we are all kitted out (eg, fridge, first aid emerg tools etc etc when travelling) and even thinking of a second hand caravan/camping trailer to pull. we have done over the last 10 years tens of thousands of k's in a ford and now the Subaru. We are wanting to do the trek from Melbourne where we live to Broken Hill/Cameron Corner, Innamincka, then across to Eromanga/Windorah?Longreach/Mt.Isa/back to Longreach/Barcaldine/Emerald/Roma/Charleville/Cobar/Griffith/back to Melb. We know this would be an ok drive for the Subaru Outback, BUT can you provide some tracks this vehicle would be able to do off-road so we can safely leave the gravel & bitumen roads and best time to do it please. We feel we are missing so much. We have always always taken our children from nappies to their teenage years with us and they now love and treasure this great land of ours in treks toFlinders Ranges, driven to Cairns, used all the little towns as the route, just about every town in Victoria/NSW/Tas/60% Queensland but yet to venture WA & NT by car but have flown to these two states but want to drive them now. BUT we are hearing the wild off road outback calling. We feel we are missing the outback by not knowing if our car will do the drives. We can't afford to buy a new car or 4wd (& caravan/camping trailer) so we are stuck (but not sadly) with the Subaru. I hope more out there would like the same as we are requesting. Any suggestions from you or other members???, your in safe km, Anton & Mary Atkinson