My wife drove up to see me finish the Ascent a few times with kids in car seats. Every time, they made an exception for her because of that and let her drive all the way to the summit. Ask at the PP Highway entrance gate when you pay your fee if they can give you a pass to drive to the summit because of the kids in car seats. You'll get a sticker in a different color or something, and then the folks at Devil's Playground will let you drive past.