There are laws governing contract worker status. You need to understand these thoroughly to protect yourself.
Yes, There are lot`s of governing rules for contract workers. Even if you work with your own EIN, at the end of the year the IRS might treat it as if you are still working for them regardless of an EIN. Let me give you a quick example: I hired a Web Developer to help me out with some web site`s that I have for some of my clients. Well, although he has his own company when I spoke to my CPA, we found out that he wasn`t a contractor, nor vendor "He was an employee. Regardless, if we was in another state and had his own company.
What you want to do is, be a vendor not a contractor. Being a contractor means you have your own licenses and permits if applicable.
It also means, you are liable for your own taxes and SSI and everything that comes with the territory.
Before you do that, check with your accountant or CPA, he can address this issue. It`s a very complex idea and to much information to give out over a forum.
As far as giving you tips, There is not simple way in breaking it down to the company. Make sure you are cool with the Owner.