We're planning a few excursions with longtime traveling pals for our October visit to NOLA. A tour of a plantation or two is on our list, but one of our friends has developed severe mobility issues over the past year. He probably will bring his motorized scooter (it can be broken down for transport) but is concerned about accessibility at the plantations. Are there stairways or other barriers that would hinder an enjoyable experience at the plantations? Many of the tours I've seen advertised seem to feature Laura and Oak Alley. Any info, particularly about those two, will be much appreciated!