When you go to save the setup press the enter button on the circuit you are driving (there should be a tick on the right side on the screen when you press enter) on then press shift to save.
It's an ITX system mainly just for downloading and HTPC use but i use it for daily use like internet, some photo editing. As for lfs it's below par but it really depends on what res you use.
Quick answer would be no because it's impossible to do without revamping whole sections of the track, if Eric wanted to make those paths drivable he would of done it when he last revamped the track, also the sections which is blocked of next to the back straights near the bridges are drivable with such layouts as this and this.