Well, From what I seen there isn't too much yet.
You should try to implement a smooth transition between your skies. Also, I didnt notice a particular order of skies (dawn -> Dusk) Thus the time_cycle doesnt seem to be very apparent, nor do I see any clouds
Besides that the base sky is very plain, and Will there be night skies?
Also, you forgot to include the car shader, I get a warning message that its missing when I start it up. (Not that I see any reason for it yet)
Obviously it still needs lots of work. Keep us up to date. Im curious to watch your skills advance.