I have created a championship called Complete Hoonatic for this. You can either add me and use it, or blueprint your own. I used Coober Pedy Trail, Coober Pedy Scramble, and Cross Track Scramble in the Outback for it, and the total distance is 6.8 miles. It is set up to only use Hoonigan cars. You don't have to win, just complete the championship.
You will need to complete the championship in every car in the pack:
1965 Hoonigan Ford "Hoonicorn" Mustang
1979 Hoonigan Baldwin Motorsports "Loki" K5 Blazer
1955 Hoonigan Chevrolet Bel Air
1972 Hoonigan Chevrolet "Napalm Nova"
1978 Hoonigan Ford Escort RS1800
1992 Hoonigan Mazda RX-7 Twerkstallion
1991 Hoonigan Rauh-Welt Begriff Porsche 911 Turbo
I'm sure there are combinations of events that are shorter, but I like how these are close to each other and you don't have to fast travel or drive a long distance between events.
For maximum efficiency, start a championship at each of the three locations for progress toward