Ursa loves the back of the Odyssey, she stretches out on the back seat and enjoys the individual A/C vents back there. She easily falls asleep, and despite a little drool on the back seat, the car cleans up easy.
Full grown, she was too big for the Volvo (with the babyseat in the back as well), and the Explorer we had was a joke.
And two crates fit nicely in the rear cargo area, when we go to hunt tests or training days. Each has her cooling mat and a big fan that runs off the car battery, and stakeouts for really hot days so they can lie on the cool grass.
Friends of mine with THREE Labs (the big male is bigger than my two girls put together) have an F-150 with a topper on the back, three crates sideways with a path up the side. But they also have an Odyssey, they can put two of the slant-front crates in the back and still have room for a platform with pull-out drawers for bumpers, collars, ropes and all the other stuff that retriever people tend to accumulate.