Please understand, this is purely from an observational perspective, having visited and photographed the Amish communities throughout Wisconsin for a little more than a year now . . . and after my first weekend experience doing the same with the Amish of Northern Indiana.
While I have read a lot about these communities, rich in tradition and largely holding to the beliefs of what is known as the Old Order Amish, much of what I read about cannot really be observed by an outsider. For instance, the Amish in Wisconsin generally do not have indoor plumbing and still out outhouses. Even the schoolhouses here in Wisconsin still have outhouses. In Indiana, however, many if not most do have indoor plumbing.
As I drove around Northern Indiana's Amish areas, the first thing that struck me was just how many farms and people made up their local communities. First evidenced by the number of horse & buggies seen out and about (even at 10:30pm on a Saturday night!) . . . and later realized while driving over rural roads and seeing the number of buggies in driveways and "carports".
I wasn't sure at times if I was seeing an "English" farm (non-Amish) or one that was Amish or Mennonite because often there would be buggies in the driveway along with automobiles. I was later told that the Mennonite and Amish are often social with one another, often traveling together for shopping trips into town, etc. in the vehicle belong to the Mennonite. I saw this personally at Yoder's Meat & Cheese Company in Shipshewana.
The other big difference I noticed was that the Amish people that I crossed paths with did not seem to mind if they noticed I was taking photos from afar using a long telephoto lens. In Wisconsin, even from hundreds of yards away I have found Amish children in particular will scatter if they realize I am photographing them. Here in Indiana, however, they seemed to be OK with it.
I asked about this at Amish Acres and was told that generally the Amish in these communities near tourist attractions and local Amish businesses have grown somewhat accustomed to photographers taking pictures. While tolerant of the practice from afar, however, they would be understandably offended and refuse to pose for photos. That really helped to explain a lot for me given that I had taken some photos of young Amish children (under age 12 or so) who seemed as if to unknowingly pose because they simply did not move to avoid the camera.
The use of bicycles in Northern Indiana was something else that I was surprised by. While I had seen bikes in Wisconsin, they largely seemed to be ridden on the driveways of their homes and not to school, church, work, etc. During my driving around on Sunday, the first time I saw a pair of young Amish teenagers riding their bikes towards what I knew to be that morning's church location, I was so surprised I couldn't get my camera out fast enough. I was later able to capture a couple of photos of the Amish going or coming from church on bicycles.
The other mode of transportation, even on a somewhat rainy and blustery Sunday morning, was walking. Many families were seen walking to or from church during my driving around. I especially enjoyed the one image I captured of three generations walking home together.
The last difference that I noticed during my time in Indiana is that they are required to license their buggies and obtain a "plate" (or "tag") much the same as what others have on their automobiles. The plate is numbered and specific to that buggy. The State of Indiana is reportedly the only state in the USA that has this requirement and they charge $25 to register the buggy.
The Amish, regardless of where I've seen them, have all been friendly and quick to offer a wave. I have enjoyed the opportunity to learn more about their culture and lifestyle thanks in part to the time I've spent reading and subsequent driving around amongst them. I hope to be able to return to Northern Indiana later this year to see how they live come summer and later in fall during the harvest.