As far as I know, the distance between your home and the office isn't really the issue. For example, there always have been sales representatives who live in one city and work there, and only occasionally visit the headquarters office. They are regular employees with all the benefits, etc.

The question facing you is more about the nature of the work you'll be doing - in particular, will you still be doing your same job in the same way, and working full-time, or are you going to become a freelancer or consultant and seek work from other clients as well? If the former, it would be my best guess that you still remain an employee and would have all the same terms of employment as you do now. The only additional issue is to decide who pays for your home-office set-up, ongoing phone bills, and travel expenses when you do fly back to the office.

You'll also need to decide in advance how you'll make the best use of phone, fax, e-mail and on-site visits (and perhaps videoconferencing) to stay in touch with the office and co-workers.