Regarding load-out, I can only speak for CAP units that lived continually in the bush and had to carry everything they needed. In addition to 782 gear, rifles, mags, flak jacket, extra bandoliers, knives, frags, full ruck, rations, two canteens, helmet (which we rarely wore but still had to carry), we had to share the weight of M60 ammo belts, HE and lume for two M79s, two radios and spare batteries, a dozen LAAWs, claymores, C4, smoke grenades, flares and a few other items I can’t remember, all told about 80-90 lbs a man—maybe more.
The reason we had to carry more than regular Marine infantry units is because the nearest ground react force for us was the nearest 12-man CAP unit. And since each CAP had roughly a 5-square klick AO, reinforcements could potentially be as far away as 8 or 9 klicks depending on relative position of each team. And if we were getting shot up bad enough and called for react, we had to have enough ammo to hold out. Generally our contacts were at night…so best case scenario, if the react unit was only a klick or so on the other side of the river, humping toward us in the dark with their full gear, chances are they’d get there in time to help with medevacs.
We had CAS and arty of course, but there was no reserve ground unit that could hop on helos and be at our poz in ten minutes.
Your assessments are probably correct, but I think small autonomous units operating independently in remote areas would be the exception.