Taking a wheelchair user

Due to lung disease my partner has had to resort to a wheelchair. We have a motorhome and can use the bus as long as we can easily reach a bus stop. He can walk a short way in order to overcome potholes and steps. We have just returned from Ferry Meadows which is ideal for pushing the chair and enjoying the wildlife. Can anyone suggest other sites that are equally convenient. Obviously I cannot manage hills or rough ground. We prefer rural and coastal to towns and cities and like CLs as much as the large sites. We would be pleased to receive any recommendations.