Because of my technical background, I am my own technical support most of the time. If you are not technically adept, find support systems. Redundancy is the safest option, and a knowledge of how to do simple technical tasks like installing a printer and locating and installing a video driver on the Internet is crucial. The phone still rings in my Boston office and voicemail picks up. For now, I still have to call in to get voicemail.
Face time is still critical.
There's no substitute for in-person contact to build relationships. If I'm not in the office, I'm not available for emergencies that require physical presence. That's simply a downside cost to working from home. I make it as minimal as possible, but it remains nevertheless. I'm certain that as a career move, working out of my home is not helpful.