Thanks to Jason, Justin, GeorgiaPeach and Apskip we have narrowed it down to this!
Teams were spotted in Santiago on the night of Tuesday the 30th, and have to be in Siem Reap by the morning of Sunday the 4th (working backwards from the afternoon sighting on the Tonle Sap). Given the confirmation of the Santiago spoiler and a refutal of the Melbourne one, shifting the timeline to two days later, does that still leave enough time for a leg in the middle?
I found only one Pacific flight leaving on the night of the 30th from Santiago airport, and this is the same as in apskip's post for flights leaving on the 28th:
From Santiago to Auckland
LA801/QF322: 2245 (Wed night) to 0355 (Fri morning)
From Auckland to Sydney
LA801/QF322: 0525 (Fri morning) to 0705 (Fri morning)
1) All teams take the same flight to Auckland on Wednesday night.
2) They would have spent eight days, for at least three legs, in South America (23-30 April inclusive).
If teams are headed directly to Siem Reap from Santiago, they'd do best through Bangkok:
From Sydney to Bangkok
TG994: 1000 (Fri morning) to 1625 (Fri afternoon)
From Bangkok to Siem Reap
PG907: 1740 (Fri evening) to 1900 (Fri night)
But in this scenario, they would be spending five days in the same city (and not a very big one at that). I draw the conclusion that...
3) Yes, there probably is one, but only one, intermediate leg between Santiago and Siem Reap.
Following the other lead: since there were six boats on the Tonle Sap and six teams were sighted on the flight to Bangkok, this probably means that:
4) The Pit Stop was probably a non-elimination. (But what happened to the African-Americans?)
5) Teams are bunched on the first flight on Tuesday 6 May.
6) They are released at night from the Pit Stop (not in time to catch the last flight at 2015), indicating an afternoon finish on the previous leg (ending Monday 5 May).
From Siem Reap to Bangkok
PG924: 0950 to 1030 (confirmed through Jason)
From Bangkok to Delhi (from apskip's earlier post)
IC854: 1330 to 1615 (most likely the case, from Jason's information)
TG315: 1745 to 2045
9W63: 1825 to 2130
Connecting through Mumbai would get the teams in earliest 2215. Not top choice for the teams.
7) No matter what flights they end up on, teams will arrive in Delhi the afternoon/night of Tuesday 6 May, and will probably run most of the leg the next day.
The bottom line:
Tue 22 April - Teams leave from LAX for Sao Paulo.
Wed 23 April to Tue 29 April - Teams spend at least three legs in South America.
Wed 30 April - Teams depart Santiago on the night of the 30th for Auckland, possibly onwards to Sydney.
Thr 1 May - Disappears due to the Date Line.
Fri 2 May to Sat 3 May - Teams participate in an unidentified leg.
Sun 4 May - Teams, very possibly arriving in Cambodia the morning, head to the Tonle Sap.
Mon 5 May - Teams run a Cambodia leg and have a Pit Stop in the afternoon, departing late at night.
Tue 6 May - Teams spend the day travelling to Delhi, arriving in the late afternoon/night.