I agree with Little Neo about checking out what works. Here is a site with some descriptions of some of the Intentional Communities. Many more can be found in the descriptions listed in the Communities Directory which is mentioned in the first paragraph on that page.

I am well acquainted with one of the oldest communities in the eastern U.S., Twin Oaks. It is a clear example of the fact that such communities CAN work, CAN survive, and can be very pleasant places in which to live.

There are many, many options as to how to make a community viable. Another community near where I live, called Shannon Farm, is set up so that the people who live there can work regular jobs, "off campus" so to speak. It sounds much like what Kat describes.

In short, there is a lot of information out there. One need not re-invent the wheel. The Communities Directory is filled with samples of workable ideas.