Great job
Of course I know it's still lot of work in progress.
I know, you can't do everything alone.
However, there are few things which could still be improved.
E.g. on Rallye: the wood planks on the start don't show proper lightmap, the whole has the same light, and the textures are stretched on some sides of the planks as if the UV maps are not correct there.
But that's just bits and pieces and causes tedious work I guess.
The borders of the dirt paths are to sharp, it could be less natural.
Therefore please add a minimum of grass. Checkout the Autumn and other Valley mods of Wraith, I think he would be really happy if you used one of them.
Some minor menu issues: when I use the back button in Nations and Star Track, nearly regardless of the menu i'm in, e.g. white track selection, it jumps to the main menu, so I have to select again Nations or Star Track.
Same for the Quit button after finishing a track, it does not jump to the track selection, e.g. white tracks, but to the main menu.
The track Star Tracks miss the "lock" symbol, but are well showing the dialog "this track is not unlocked".
Btw. Star Track Stadium D1 has no lightmap.
And generally, you could still add some more decoration.
Snow A1 looks a bit strange, with the wood planks floating in the air without any support
