I'm in a similar situation...
Our mission statement is: thousands of miles of highway and then hundreds of miles of nasty gravel washboard. No 'wheeling' involved. We need something that can cruise the black slab with minimum driver input and then suck up the bumps of bad gravel without shaking everything to pieces...
Considering either a Toureg or a Cayenne or an ML 500 (of 55 AMG)
Keep talking guys - this is helpful to me too!
Porsche Cayenne S "TropiCayenne"
Honda Ridgeline - go ahead and laugh