What can I study in college if I want to do something having to do with wilderness survival, hiking, etc.?

Sounds like you have a good plan and a great career choice, always try to do what you love if you can, you will be that much happier and better at what you do. I would major in Environmental Science (a bit math & science intense), Environmental Studies or Wildlife Biology are also good choices to help get you where you want to go. I'm not sure where you live or where you would like to go to school. I have attached 2 links for schools that are reputable for these programs. SUNY ESF is regarded as the better of the two but Ramapo College is a solid school as well. Good luck!