Without a doubt the remaining iron bridge and the renovated tracks nearby are the most frequently visited site on the TBR. Only true aficionados venture to other portions of the TBR, if they even know that they exist.
After completion of the TBR, almost all of the Allied POWs were re-located to a series of camps in the Kanchanaburi area. From there many were sent on to either Japan or French Indo-China. The US POWs spent a majority of their captivity at the camp known as Thamakam near the tracks that approached the wooden bridge. Modern commercial development has removed all traces of that camp.
After some the Dutch POWs in that same area were killed by bombs aimed at the bridge, some if not all of the US POWs at Thamakam were moved to the Chung Kai camp. We know that LTC Tharp himself pent some tome at Chung Kai since a portion of his diary was buried there and retrieved immediately post-war.
It was no uncommon for the POWs to bury documents, drawing and the like in the graves of their comrades with the knowledge that whenever the war ended someone would come searching for those graves.
There are many references to Camps 1,2 3 & 4 at the Thamakam-Kanchanaburi site but I have yet to see a map detailing where those are located.