Wright sketched several pictures of Broadacre City, and with his students built a large model showing what a typical area might be like. Some views can be found on the web through Google's image search.
Broadcre City is not meant to be enclosed in the manner of small towns or isolated rural farms. Life there would be enriched by its linkages; Broadacre City celebrates mobility, not small town locality.
Wright's claim that isolation only has value if it can be broken at any moment shows how his proposal is not an individualist utopia for self-sufficient pioneers. It is a linked society, with its links defined by the technology of his time. Were it built today it would have more kinds of links.
Today's denser links produce the opposite problem; insistent connection that needs to give way to isolation at times, finding calmness in a sea of flows. Given Wright's dislike of the crowded city, perhaps our condition would not surprise him, and for an updated Broadacre he would need to invent new kinds of distancing as well as new kinds of linking.