Generally it is only 12 hours.
so if they arrive in at 3am in the morning they are out for 3pm.
But in that time they have to do interviews, eat sleep. So they probably only have like 8 hours to sleep and eat.
I think the longest rest period was 60 hours and that was in season 1 because a storm in the desert caught them. And the shortest I believe was 10 hours to allow teams to catch appropriate flights.
Normally if they dont tell you what time they came in at means it was more than 12 hours.
This race was filmed in 21 days apparently as they dropped a leg or two as apparently no non elims. But yeah - racers are normally away for 5-6 weeks as they are flown to the start city a couple fo days before the race starts.
this is a reaaly intersting breakdown of the logistics of TAR -
http://en.wikipedia.org/wiki/Amazing_race
