I've slept rough a few times. The thing about it is that's it's a surprisingly complicated process. A big element of that is fear and the presence of danger. That's immediate fear and danger from people and the long term fear of not having the money for food and what have you. And the general uncertainty of that sort of life. (I would add the caveat that, as a busker my times sleeping rough tended to be only for a few days or a week at most and I was better equipped to deal with the weather etc... than most long term homeless people.)

Bottom line, the more genuine your experience, the more dangerous. If you do it, I would go along with people you've known for a long time. You'll be that bit safer and you'll see how they live. Plenty of homeless are willing to give a hand to newbies. (The problem is that you haven't known them long enough to trust them generally. Easier if you haven't got anything worth stealing and you can handle yourself in a fight though.)

If you're going to do it, I would make sure it's fairly warm. It's really horrible sleeping out in the snow and particularly risky if you're not well equipped/haven't eaten in a day etc...)