I might go around Valentine, start a stranger mission and then fish while the timer runs out, then go hunting and maybe find a wagon and go fishing, or find nearby hideouts. I get about $150-200 after maybe 1-2 hours.

New Austin I do the same but usually stay in the far west since there are a bunch of hideouts.

Lagras is also perfect for this, and it has birds and gators that give good money too.

Frankly while it was much easier to make money killing swarms of birds over Saint Denis, that became the only thing I was doing after some time. And it makes no sense for an outlaw to make a fortune selling feathers. So now I'm forced to roam the map much more and I'm enjoying myself a lot more.