If your beans and toast are bland that's a you issue. Learn to spice beans or but better beans, I kinda imagine you slapping plain boiled lima beans on a slab of dry rye and wondering what the hype is about.
Cowboys were quite literally in the middle of nowhere with nothing but beans. What's the British excuse? "Oh, my great grandmother cooked this in the blitz, and we forgot rationing ended decades ago".
On delivery, not when they're out in the field. Where would they even put a whole slaughtered cow? Especially with all the salt they'd need in pre-refrigerated times. Even with a wagon, that's not an efficient way to bring food with you.
On the chuck wagon, the same way they would carry beef they didn't slaughter on the go with the bonus that slaughtering as you go prevents you having to carry extra weight on the wagon until you actually need to. You know with beef being self propelled until it's slaughtered and all.
You carry the salt anyway. How do you think they prepared meals the hunted? It's far more efficient what are you even on about.
It's like you've never read a book or at the very least played Oregon trail.