Green Card these days can be taken as a slow or fast process that solely depends on your eligibility catagory. EB2 for World Wide is Current. So if you fall on EB2, you can apply for your Labor which is likely to get cleared in 4 months from the date you start. Then you have an opportunity to file I-140, I-485, I-765(EAD also known as Work Permit) and I-131 all together. Once you have a work permit in hand, you can go and work any where you want. Granted that your employer filed your petition on your behalf, you are not required to work for him until you have the GC on hand. In some instances with the American Competativeness of 21 century allows you to change your employment once the I-485 is pending for six months when I-140 is cleared. At this stage, even your employer wants, they cannot revoke your I-140 petition. Filing AOS or I-485 is what you do on your own. Employer has nothing to do with it. After your H1B gets approved, you are no longer in your previous status. Meaning if you come to US in F1 visa, upon H1B approval, your status should read as H1B of which your newly issued I-94 will describle the duration of your stay in US. People with H1B status can go to school, but in order to maintain the residency, in many cases school by school, they have to stay in a state for a year and should maintain the residency. You need to check with your school what are the documents that prove your residency status where you may eligible to pay in-state tution. Filing a Green Card won't give you status instantly. If you file GC in your H1B status, till it gets approved, you are still in the H1B status. Once you are eligible to file EAD, and when you start working on EAD, you will lose your H1B status and come to stats which is commonly known as Adjustment of Status (AOS). At this time if your GC petition is denied, you will lose all your status, so its really important if or not you want to work on EAD. If your job is stable and you are not looking to work in others, then I would suggest you to stay in your H1B status. Even getting GC, you still have to maintain your stay in a state for more than a year in order to file for in-state tution. So getting GC in NY wont let you file residency to study as an in-state student in CA. I hope this helps. If you have futher question, let me know.