Don't forget, in addition to you bumper to bumper warrenty, you've got the lifetime powertrain warranty!
The Patriot seems like an extremely practical and economical basic transportation vehicle but I can see how it would not be large enough for soccermomming. I looked at it for my commute and was very impressed.
As for your mileage, keep in mind that it will increase as the car breaks in. Everything is tight right now. Also, you may be able to use more tire pressure without causing uneven wear.