Unfortunately never been to Thunderhill...
Been about half a dozen times to Buttonwillow (clockwise, #13 configuration: nice track, very technical, first 1/3 of track is narrow
and slow, gets wider and flows well after that ) with different track day org. all good ... a
The only average note I would give (like a C): Trackdaz, got rear ended by
some crackhead on a Gixxer and another time, one of the instructors
crashed right in front of me (WTF ?? ).
Another point I want to make is for anyone out of state willing to burn
some rubber here in SoCal: gotta try Fontana (aka California Speedway
now: frickin AutoClub Speedway), great track, lots of runoffs and going
170+ on the banking is fun..
Fastrackriders has the exclusive deal with Fontana.