World Champ tracks I know of for AC (legality is up to you guys).
Kyalami 67 - Mod
Monaco 66 - Mod
Mosport - Mod (any version available, the layout hasn't changed)
Watkins Glen - Mod (Classic short (No chicanes) is closest I know of to the original layout)
Monza road '66 - AC Stock
Silverstone '66 - AC Stock
Nurburgring - AC stock if we run Nordschliefe, Mod; if the classic Nurburgring I've seen about is any good/legal
Rouen - Mod (longest Layout) - (Should be Le Mans Bugatti, But A. I don't think the tracks been made in AC. and B. It's rubbish, even the drivers said so at the time.)
Zandvort - (mod for historic layout, but this is very good)
Spa '66 - Mod. modern would work but isn't 'right' in GPL terms as most of us are likely to finish the race.
Mexico City - Mod (but graphically it's rubbish, and the '88 layout)
Non Championship include Brands, and Oulton from stuff we know is good - and Jarama which I think I've seen knocking about.
Based on all the UKGPL races over the years they can be raced anywhere and still guarantee a big grin, any historic/classic track would be awesome