Others have covered this, but if your 14-day pass isn't attached to a package, you might consider buying an Annual Pass for one of you. There are some other perks associated (like dining, merchandise and recreation discounts) that you might be able to use. I know UKers often get a good deal on those 14-day passes, but the AP might work out well for you. And I think parking is $14 per day, so if you go every day, that's $100 just for parking. That might cover whatever difference there is in the 14-day and AP. (Although water park admission would be an issue if you are planning on doing that a lot, so you'd have to look at the premium AP cost.)
I was supposed to be in Newcastle right now! Darned volcano...we have some work to do there but it's been postponed. I've never been north of London so it'll be a new experience.