The Ranch Style Home is what I would recommend for retirement. The modern ranch house has improved over the years and offers the best flexibility in design for seniors.
The Ranch House can come in various designs but they all provide living space on one floor.
One of my favorite designs is the Mid Centruy Modern.
What I like about Ranch homes is they typically offer open floor plans, wide hallways, large closets, which is good to accomodate walkers or wheel chairs.