You need one letter from your employer, that is it.

As long as you have employment letter, bachelor degree, canadian passport, and prepare other documents according to uscis website (http://www.uscis.gov), go to border, you will get it in half hour. You will be asked some test questions to see if you know the law. Basically you are not allowed for any other employer etc. Don't pay any consulting fees. If you have basic common sense, that is all you need. It does not cost company anything at all. Good luck.