A more permanent alternative is a brick or stone patio built around the raised beds. This keeps weeds down, doesn't need to be replaced, and wheelchairs can easily get around on it. A disadvantage to this is that it is more labor intensive and expensive to install. Once you have the raised garden built and easily accessible, you need to decide what to put in the garden. A good, foolproof choice is annuals.
Annuals provide instant color and come in many shapes and sizes in a wide range of colors.
Put the tall plants in the center or back of the bed, and work your way down to the shortest plants in the front. Plants that drape over the side of the bed, such as lobelia and petunias, are good for the edge. Hardy perennials can also be grown in raised beds. It will take the perennials a year or two to get established, but after that they require very little care, and don't need to be replaced every year like annuals. When your garden is planted, it will require very little care.