Rookie run must be on 4th course. Assuming good rookie run they can move onto any short or combo course or actually stay on the 4th course to continue licensing. To qualify for long course they must run 175+ in the 2 1/4 on any short or combo course.
IIRC, last year course 1 was a dedicated long course, course 2 was a combo course, course 3 was a short course and course 4 was the baby course. Or both 1 & 2 may have been combo courses but I don't remember. I worked as a starter on course 1 and I don't remember seeing many or any short course cars.
Regarding licenses, if rookie run is over 125 but under 150 they get a D, 150-175 is a C, 175-200 is a B, 200-250 is an A and so on. A licensing driver can qualify for the long course on the same run as their B license run if they run over 175 in the 1/4.
No speed limits on any courses AFAIK.