The way to make it perfect would be a national high speed rail network connecting all the major and mid sized cities to all the national parks accessable within the lower 48.

Would basically annihilate fuel emissions for mid-hop travel since going by train is less costly than air travel and competitive against gas costs over similar distances.

I'm no patriot and am even planning on moving across the Atlantic as soon as it's practical, but I will show nothing but praise for our national park system. To have a country as exploitive as America see great, resource rich prime estate and say "do nothing with it" is incredible, and the parks themselves are beautiful. So much needs work here, but our parks are worth preserving.