I have crossed there many times and never had a problem. I imagine that crossing there will entail what it would almost anywhere else. The Vermont part of it is a pretty drive and it isn't far from Montreal. There is a main crossing for the New York interstate adn one for the Vermont. There are also some other crossings in small towns off the beaten track. A good way to avoid lines. I would contact Customs and Immigration and find out what you need. The US wants your money though so barring any reason why you shouldn't get in (criminal record, you do something you shouldn't like smuggling) I can't see why they wouldn't let a nice limie chap and his family into the country. You are allies after all. Have a nice trip!