Yes! Combining countries and minimize long, expensive flights is the way to go. My dad took me to China a few years ago, and we just went to China. I said, can't we at least add on Mongolia? I really want to go to Mongolia.
I also agree that finding a place with a kitchen is a super saver. Cooking saves big. I do like to eat out more when I'm traveling because trying new foods is a big part of why I love travel, but just cooking three or four dinners a week helps a lot.
I think you can add Belize to that $1000 a month range. We live on that. There are five of us, and a chunk of that is visas for 5, but we also rarely eat out and rarely go on pricey adventures.