I did a career day recently for a high school summer program I did eons ago. I got the question afterward, about what major to pick for someone interested in "mainly math, physics/chemistry, and economics" and interested in graduate studies maybe in economics. I hadn't thought about picking majors in a long time. These were my thoughts, but if anyone else has thoughts...
At the end of the day, it doesn't matter too much what you major in, and you really don't need to know what you will major in, until sophomore or even junior year.
I do think that math is probably a good baseline though, as it gives you a lot of flexibility in the future. Esp if you want to do graduate studies in economics, a math degree with a few econ classes, is probably a good solid flexible preparation (you can take that in a lot of directions, including law school even or finance, which is a typical route people find themselves taking to make a lot of money). But major doesn't really matter.
To do grad studies in economics, you just need a few econ classes and a strong math background (either from a math minor, or a physics degree, or an engineering degree), and then your major can be whatever you discover you like. In high school, it is really hard to know. College is a good time to explore, and consider weird things like cultural studies, anthropology, political science, philosophy, sociology, history, education, etc. I think if you do wind up pursuing economics, or whatever, it's nice to have a solid foundation of different ideas for inspiration.
As for which programs, that's hard to say. I think what you'll learn will be pretty comparable anywhere you go. Heck, all the professors went to the same few grad schools. So I would pick that based on ranking (I do think ranking matters in that it affects the quality of your peers), geography, size of school, etc.
College visit might be important, but don't put too much weight on your gut feeling. There is some evidence out there that the weather the day of your college tour is a big determinant of how much you like it there. People like schools much more on sunny days than on rainy days. So things like weather could easily bias your decision.
Hope that helps.