Is dorm life essential to building connections so that you can be updated about research opportunities and internships?
I'm going to say no, probably not. There is the off chance of finding one person who actually has legit connections that lives in your dorm... but the chances are pretty low. I think you're better off talking to professors or advisors about that sort of thing. Don't discount your family or family friends, though! A family friend of my boyfriend's family is the mother of a girl who was asked to do MD/PhD (she declined). She knows the guys at that university. That may end up working out for me. That's not guaranteed either, but it can be hard to get connections in general, and dorm life will most likely not do that for you.
Do you think dorm life will enhance your pre-med experience and help you on your path to getting accepted to med school or do you think it will be a distraction?
To me, it was a distraction. Totally and 100%, even though I had a single. People are loud and obnoxious, and they interfere with your life. If your main goal is to get into medical school rather than making friends, then I don't suggest living in a dorm. (I only live in a dorm because I can't commute.) You will make friends in your classes and you could always drive back to campus to hang out with them. Not to mention, when people are partying hard you have your house, which is probably a lot quieter than a dorm.
Do pre-meds do better if they live in dorms or commute?
I've never commuted, but I seriously believe that I would be doing a bit better commuting. At least in my dorm, people are very noisy, sometimes blasting music in the loud bathroom at 3am... It's not conducive to sleep, which can really impact performance. Not to mention, it would also be hard to focus in your room for the same reasons, especially if you have a roommate. (Trust me, noise-canceling headphones, even the best ones on the market, are not designed to block out that kind of noise.) It's just a very distracting environment all together. Just commute. It'll save you money, also. Because trust me, the dorm experience is not all that spectacular (unless maybe if you're just a visitor).
Whether you want to be social or not is up to you. I do fine with a handful of close friends, which I could easily drive to campus to see if I end up getting an apartment.