It's possible to be a successful owner-operator using a cargo van, and even to find your own loads. However, those who know how to do so are unlikely to be forthcoming with the information because it's a VERY competitive market due to low barriers to entry. You're far more likely to be successful if you lease on with a company that has an authority already and learn a bit more about the business.
If, after a year or two, you still want to do it yourself, you might be able to find a tiny company that will let you learn a bit more about the admin/dispatch/sales side of the business, but I wouldn't count on it. No one wants to train their competition on how to effectively compete with them. That's probably part of the reason why there is so much compartmentalization in this industry. Intelligent owners realize that by not training people to "do it all", they can avoid having a bunch of ambitious upstarts with the knowledge to truly compete with them in the marketplace.
I don't want you to think I'm discouraging you. I'm not. I
was you.
But now I'm them.