The Outback has a traditional station wagon split to it with a fairly large cargo area and a decent back seat.
What I do is fold the back seat up, but leave the seat back in place. When I put down a bunch of padding, and some quilts, and voila, Mason has a nice area to ride in AND I have all of the cargo area in the back to carry my luggage, his food, etc.
The way I did it with Ruger and Nikky was similar, but I folded the seat backs down. Then I had a piece of plywood that I used to replace the seatbacks. That way was a bit more convenient when I had two of them, but with only Mason, and the fact that he is a LOT taller, I have to leave the seat backs folded down.
In the Forrester, the cargo area is very small in comparison to the Outback's. It's a family SUV, but because of how it's arranged, it's really not all that hot on the utility part of it.