My dad was a flight engineer on C130s out of Pope; I know exactly of what you speak although I never experienced traveling in one myself.
My favorite story of his was when the US sold some C130s to Saudi Arabia back in late 60s/early 70s. He went over with the planes to train the Saudis. One day his crew along with some Saudis on board were flying from point A to point B. The crew suddenly smelled the most horrible odor and couldn’t figure out the origin.
Turns out, they were airborne during tea time. The Saudis had built a fire in the cargo hold with the dried camel dung they carried with them and were brewing their tea.
Dad said the rest of the flight, the crew had to wear their oxygen masks.
YIKES!
I’m appalled, but not surprised.