There are a ton of free resources online to learn just about anything you could ever need to know about systems/networking/programming.
Linux isn't a bad hobby to pick up. I find that most tech people can't even use it. However, it really feels like a niche market, and there's a bit of a learning curve (as with anything).
I don't know much about networking, personally. But there are guys who exclusively do networking and they seem to make pretty decent money (more than decent). Just about any kind of Cisco/Juniper/insert-network-vendor-here type of stuff requires someone who specializes in that kind of thing.
Windows sysadmin stuff is probably the easiest to learn, since there is a lot of GUI involved. However, large Active Directory environments relying heavily on group policy can get pretty confusing, quickly. I also get the impression that there are a lot of Windows admins out there, resulting in less pay and more competition. Everyone seems to know the basics, but the more advanced stuff is known by far less people.
You can't really go wrong with programming. There's a massive demand for it. I don't think you really need to be a GOD to actually make a livable income from it either. Most people, flat out, cannot program. At all. So you're already at an advantage if you can do it, period.
Unfortunately, the "break & fix technician" jobs pay absolutely dogshit money and they're all part-time roles. Which is really a shame, because I really enjoy building computers and fixing broken ones. However, you're likely to end up in a Geek Squad or similar role making about $14/hr working maybe 30 hours per week if you're lucky, with zero health insurance.
I've also heard there's some kind of Apple/Mac admin niche market, but I'm not too sure about that.
Sorry if I didn't leave you with a smoking-gun type of answer to your question about which roles to pursue. Maybe shoot for NJ datacenters/hosting companies? You can take a lower level position there but you'll learn a lot of neat and useful stuff very quickly. Mostly about hosting/email/Linux/networking/internet/maybe-Windows. And you can move up to a sysadmin role down the road or maybe even become a "networking guy".
Maybe also consider learning AWS (Amazon Web Services). I see a lot of jobs asking for that these days. They're mostly the Linux sysadmin/engineer kind though.