I was with Hugh Mills in RVN in 1969 and I can attest that some of what was written in "Low Level Hell" actually happened to other guys. I suspect that the ghost writer put the stuff in to make the book more interesting. The unit was Troop D(AIR), 1/4 Cav and was the only organic Air Cav Troop in the 1st Infantry Division. When the 1st Infantry Division stood down in April 1970, the Troop D outfit was renamed Troop C , 16th Cav and we were sent to Soc Trang and later Can Tho in the Mekong Delta in IV Corp. We retained the same people (almost), aircraft, call signs, and even radio frequencies. I think that the only people that went home stateside (Ft. Riley, Kansas) were the Commanding General and maybe the Sergent Major.
I was later assigned to the Cobra school at Hunter AAF after my tour and Hugh came through the Cobra qualification course enroute to RVN again, and Back to Troop C. I last saw him at the VHCMA convention in San Antonio in 2005. I think he is working on another book.
As for Cambodia, Troop C was involved for about three weeks in May 1970, actually about 2 weeks after the first incursions at the "Parrots Beak" in III Corp.
My impression of the unit compared to others is that we flew a lot more than any of them. I left with 1277 hours of combat assault and we had a couple of pilots that had over 1400 hours, all in one year. It was mostly "pink" teams and a lot of guys got shot up. It was not a pretty time and few of us stayed in the flying game. There is a Dark Horse web site that you can visit which was put together by one of our Huey crew chiefs. It is darkhorsevietnam.com.
I still fly and am fortunate to earn part of my living flying a UH-1H on contract for the Oklahoma Bureau of Narcotics looking for idiots that grow marijuana outside. We do this in the Eastern 1/2 of the state. I like doing it because these cops are the good guys.