There are several tour operators in Lancaster. I'm not sure which one you are going on. The tour operators are not amish, but have made a "deal" with some Amish folks. You may be lucky to be going on one of these, in which you will visit a real amish...
Check with the organization that you're sewing for - they may have specific requirements because of wheelchairs. I've seen them ranging from 37" x 48" on up to 45" x 55". If the quilts do not have a wheelchair restriction, lap quilts range from 52" x...
We lodged in a Marriot - not sure which city. It's great fun down there, though. Lots of buggies and huge Amish families. Enjoy yourself :0) It won't be hard.