Hello!
Just discovered this most excellent site 2 months ago and registered on the forums to chime in on this post.
I have an 06' Outback XT turbo that I adore, with 170k miles, however it is not with its caveats. To address a few of your points:
Where do you live and where do you plan to do your camping? Reason I ask is I just moved up to Washington from California. In California almost all parks and campsites are either paved all the way to the top, even to the trailheads at 9,000 feet, save for sometimes a nicely graded dirt road navigable by 2WD vehicle. However, now that I'm in Washington, even the popular trailheads require a half hour of driving one way on some pretty bumpy dirt roads just to get to.
Advantage of Subaru vs other AWD vehicles: beefier suspension. I had a solid Honda CR-V before, but its suspension was just not up to the task. The beefier suspension however does add to the weight and the Outback is pretty heavy. The Subaru AWD is also pretty smart in that if you get the car up on 3 wheels, the system will transfer the power to the other three wheels on terra firma. Some AWD systems are smarter than others.
However the older Outbacks don't have the best mileage... my '06 gets about 19-23 mpg combined which is SUV territory. The main advantage of the Subaru over the SUV, IMO is the lower center of gravity yet still having high ground clearance. When I switched from my Honda CRV to the Subaru, it made a difference on the really winding, narrow, paved roads of northern California. If you are living out in the desert southwest (AZ, NM, inland southern California) and need to drive through rutted dirt roads after the rain, an SUV will give you better approach angles than the Subaru. If you camp at unestablished sites and need to do an 11 point turn to back out off of a single lane mountain dirt road, the Subaru has better visibility than, say, a pickup with a topper, and will make this task easier.
If you are interested in camping in your car, the Subaru Outback actually sleeps two adults (I'm short, at 5'5", though), whereas a 4Runner might not. The newer Impreza wagons are large enough to sleep in. I think both the newer Outbacks and Imprezas get 30+MPG.
Newer Subarus get much better mileage than the 04-07 era.