Good find dude, that looks pretty interesting.
For one, Apricot Hill looks very much like some of the test track sections from the licence tests. I wonder if originally many of the licence tests used corners from that circuit as the sample corners? And the Rome Short course looks like it has a similar texture to Red Rock Valley, with the colour of the track/skyline etc.
Those hidden tracks are very awesome too - the penultimate one, the big rectangle, looks a bit boring and pointless to drive on, hence why it got cut, although I'd have loved to have seen it evolve into something like the final track on Ridge Racer Type 4...perhaps that's another reason why it was cut, that it was too similar to RR? It's main rival in the racing game stakes on PS1 at the time? And seeing that they had Cote d'Azur ready to go on that game....man. I guess it meant less work for GT3, as they basically already had it. Still really sucks that it wasn't around in time for 2, would've been awesome to have an enduro there or something.