I can't comment on the tracks you have mentioned however I can add my thoughts in re to the touring van. Almost two years ago we bought an on road Flamingo ST, it is set up for short term off grid camping including solar, battery, two water tanks, gas hot water, shower/toilet etc.
We tow it with two different utes and also a horse truck. It tows great with all three and has never been an issue.
We bought the on road due to availability and costs. The same van in the outback model when we were looking was more than 10k extra. No way could we stretch to that.
If money was not an issue, I would 'like' the outback version only for the height with exiting gullies etc. In saying that, the only time we have bottomed out was in a caravan park that had a stupid set up.
We tow on road and gravel roads mostly. Hubby is also confident to take it on some sand tracks however we have not had holiday time off to do this. We also go to showgrounds when showing and some of the site are 'interesting' to get to.
If I was doing it again, I still could not warrant the extra 10k to buy an off road version with the travel that we do.