Planning way ahead could include making doorways wider (at least three feet), and at least one bathroom wheelchair accessible. Halls should be at least four feet wide, and you need space to maneuver a wheelchair or walker in rooms. You have to think about sinks, toilets, appliances (a front loading washing machine, for instance), electrical receptacles, showers, grab bars, lighter doors, door handles, etc.; and if you have more than one story, you may need an elevator or powered stair ride. Some people plan for a bedroom on the main floor. Hardwood floors are good for wheelchairs. Do not put the toilet in a closet. Avoid changes in elevation--stepping up and down in the house. (Ernie White enabled us to avoid that mistake in mother's house. He pointed out the problem and raised the floor in the back porch room to the same level as the kitchen and the utility room.) But vary kitchen and bathroom countertop heights.
From Building a Cool House for Hot Times without Scorching the Pocketbook: Amazon.com: Building a Cool House for Hot Times Without Scorching the Pocketbook: Books: Joy V. Smith