So do you already have 2 kids or are you doing long term planning? I'll answer 2 ways. If you're just planning, buy a manual transmission Subaru Impreza. Why? They're cheap, have "real" AWD get about 30 mpg and avoiding the biggest problem (the CVT transmission) gives you Honda kind of reliability (well Honda manual....their CVTs also have issues).
Ok, so if you already have 2 and might have a 3rd, I guess I'm sorta stuck. Ford Fusion, perhaps? They do come with AWD and I've noticed that a ton of new ones come in AWD. Nice and big. Not big enough? Taurus? They're huge.