Taking this comment seriously I would actually really support a more walking centered park system. You are correct that a lot of most parks are situated very far from roads, but in a lot of parks the best places are close to the roads. Personally really dislike having a traffic jam in a natural park, or people demanding yet more parking spaces in Yosemite valley. The shuttle bus services that exist in several national parks are generally really nice. They ease up the footprint and maintenance costs of roads and parking lots. They make it easy to do some of the more interesting through hikes. Obviously I am not saying that we should scrap all the roads but I do think that emphasizing walking would be a good idea.