My exact numbers might be off (which is kind of a problem it seems on HN), but the point still stands - you can add practical amounts of range by having the car just sitting there, even in places where there's not that much sunlight.

Besides, I just checked out panels, and there's a lot of 500w ones that are appx 1mx2m, these station wagons are huge, easily 2m wide and 5m long, half of it a flat roof, so its not outrageous.