I have read that the overall 'feel' of the movie was an accurate portrayal of Vietnam in much the same way that Jarhead portrayed the boredom and monotony of war - especially the Persian Gulf conflict.
My question involves a few peculiar and awesome aspects of Apocalypse Now. They all have to do with how accurate this was to real life.
I'll do my best, although it should remembered that many aspects of Apocalypse Now are unverifiable, some being inventions, others based on Michael Herr's Dispatches, a vivid but rather chaotic book based on his memories of his time in Vietnam as a war correspondent.
The 1st Cavalry Division traced its lineage to the horse cavalry, but it was in no means the same formation, and its descent was complicated. The last US Army horse cavalry units were disbanded in the 1930s, with some becoming armored, others infantry. In WWII and Korea, the 1st Cavalry fought as regular infantry, despite keeping the moniker. The 1st Cav of Vietnam fame began as the 11th Air Assault Division, a test unit used to experiment with the new concept of helicopter-borne infantry, but was reflagged as the 1st Cavalry Division just prior to deployment to Vietnam in 1965, and assumed the traditions of that formation.
USO shows and other rear-area diversions were a feature of Vietnam, but I am unable to either confirm or deny their presence in that exact area.
No, soldiers did not pay for their own supplies, unless they were acquiring them irregularly; ie, they were not authorized to draw supplies from a given area and were essentially buying them on the black market. Troops in-country were paid in military scrip, in an effort to keep down black market activities, so there wouldn't have been many (if any) people walking around with pockets full of greenbacks.
Interdiction of the Mekong River was a major US Navy priority throughout the war, as it was an artery of supply and reinforcement for VC/NVA forces. Gunboats, usually in small groups, operated as far upriver as the Cambodian border.
There were certainly isolated border outposts that came under a great deal of pressure, most of them operated by US Special Forces in cooperation with local ethnic minorities, mainly Montagnards, Nungs, and Hoa-Haos. But the idea of a base which is completely forgotten about and in a state of leaderless chaos? I'm afraid that must be chalked up to artistic license.
No, there was no Walter Kurtz. Aspects of his character may have been inspired by Colonel Robert B. Rheault, a high-ranking Special Forces officer who was court-martialed after authorizing the assassination of a suspected Viet Cong double agent.