I would think Maxwell and the AFHRA are your best bets.
Being that it was an A-37, it could have been doing a number of mission profiles. Do you have the MACR on it? I am curious to see if the crew list was one or 2. If it was listed as 2 that would make sense. If only one, I have a couple of theories, but nothing that would be backed up in any official records. There were a lot of little black ops in Southeast Asia.
This was one of those instances where the crew consisted of one, that day, that aircraft, that unit, that province.
I base this on the fact that there were no other USAF or Army personnel KIA or MIA that day and in that area or doing aviation - from the records I've seen.
I lack the full MACR directly related, but feel that one can deduce his being the sole crew based on what else is NOT present in the available records.
In further reading, again projecting somewhat, the crash took place somewhere near a Navy Riverine depot of some kind - I believe. In any case, I think the old map shows a schematic of a small landing strip within several yards of a Mekong tributary... and the fragmentary records do, I recall, make mention of units like his doing "clandestine" sorties into Cambodia, Laos et al.
That made me think Black Ops too... in which case those who do know won't say even if they are still with us.
Your thoughts on this are helpful. Thank you...
Naturally, this can be a totally wrong conclusion... as happens sometimes.