<font face="Verdana, Arial, Helvetica, sans-serif" size="2">As far as I understand, Amish who are traditional enough to avoid any photos of themselves are also prohibited from using any mechanical means of transportation.
Lancaster County, PA is a heck of a long distance from the Canadian border. Did he do the whole thing in a horse-drawn buggy?</font>
Elaborating on the post above, in some Amish communities it's OK to take advantage of cars, planes and buses so long as you don't own or operate them. Similarly, Amish typically don't have freezers in their homes, but many rent freezer space in a shop near their homes.
As for being able to come home to the US without a passport, my brother also made it through immigration without his passport. I was with him at the time. Without thinking, he had put his passport in his checked bag. When he got to US immigration in the Virgin Islands, he explained what he'd done and was waved through in a matter of seconds.