Peter, Just going from memory, But didn't Lt Davids forceland on a sandbar of the Waffir River? This is not near Hopoi(which is on the coast between Lae and Finchaven). It's actually the next river junction upstream from the Watut River and the Markham River, in the Markham Valley. It's the same River(Waffir) that Lt Thorvaldson forcelanded next to(although more succesfully than Lt david). I visited and photgraphed Thorvaldson's P-40(with Richard Leahy) in the 1990's prior to it's recovery and restoration to flying condition by Precision aerospace and Mike Spaulding(the P-40 is now flying out of Mareeba,QLD). I never saw David's P-40 at the time of my visit and local villagers were not aware of another wrecksite in the vicinity(a P-47 in the mountains some miles west was the only other crashsite they knew of, Richard had already visited it). I believed then as I do now that the Waffir River had covered the wreck with sedimentry gravel over the intervening years. This isn't as far fetched as it seems, as the Markham and Watut Rivers have, since 1945 covered over a B-25, a P-38 and a P-39. we have wartime and post war pics of the crash sites and today the rivers have erroded away the banks and covered the wrecks. Amazing stuff.
Hope you get a successful outcome with the sale/swap of the project. I would like to think and airworthy P-40 with wartime provenance might value close to USD$3,000,000. But as you know, I am biased with a self interest.
Cheers
PS There is a famous wartime photo of a P-40 that did forcelend at Hopoi and was covered with palm fronds to hid it from the enemy. Cant recall the details, but it is on
www.pacificwrecks.com