Originally Posted by rkkwan
Crossing the border by land is a lot less painful than going to the airport. No forms to fill, no security checks.
I believe OP isn't visa-exempt/waived so he and his family will have to get out of the car and go visit immigration with passports and completed I-94W and customs forms (fill out in advance), $6 in cash each for entry fees, and maybe proof of return to the U.K., get processed and all. If there's no traffic, shouldn't take more than 5-10 minutes.