I know that I've written about this some before. I keep thinking about it from time to time, especially walking through neighborhoods.
My hypothesis is that many of the abstractions of life lead directly or indirectly towards unhappiness, broken societies, and environmental harm. Trash collection leads to no feedback loop of waste. Cities where it's easier to be unknown than known optimize living as an untrustworthy person. And lack of ownership correlates with lack of equity. Having equity gives you more to be responsible for.
I propose, in my hypothetical mind, that there are three ideal units of people (from a physical location standpoint). Individuals, families, and neighbors.
If your home is your homestead; your farm, your water source, your generator, your trash dump, your septic tank, your garage, your house; you see the cycle of life before your eyes. You see the trash you burry next to the garden. You see your truck's oil leak dripping down near the well. First and foremost, your choices impact you before anyone else. If your home is not your trash dump, you do not see the waste you create. If your home is not your farm you care less if it can sustain life.
Thusly, I think family are the people you feel comfortable sharing resources with intimately. Using their poop as fertilizer for your crops. Burying their trash next to yours. Them trusting your hand at gardening and farming. Perhaps, these are the details too intimate for capitalism to handle. They are best handled by close knit relationships and common values.
Of course there's more than one family on earth. Quite a few, in fact. And if say you decide to have these homes near one another, neighbors can contribute greatly to security and trade. Of course such requires an actual relationship. Most likely more distant than family, but still an investment of time, of which you can only have so many.
Now easy home will have so many units of people in the family. And each neighborhood will have so many units of homes. The average family size has shrunk notably, but perhaps four can be an average number. Of course you don't want four to be squished so that's the most it can grow. And yet, you want the space to have the home largely self-sufficient.
I would say any homestead has a minimum size and then a fixed rate per person added onto it as load for extra trash, water, electricity, and food. Maybe this is a two acre base, then one acre per person. Maybe just one acre per person is enough. I don't know. I bet it depends a lot on the fertility and utility of the land.
Modeling a neighborhood based off Dunbar's Number of 150 connections, I would imagine planning for twenty homes near eachother. Average occupancy of five. This would allow for 50 connections outside of the neighborhood. I'm not sure of the optimal ratio of connections near by and more distant, but 2/3 near by is probably reasonable.
Of course, you could also model it based on families knowing one member but not the entire family. This may be more realistic. Say the families have 1-10 members each, but only one needs to be known for a strong neighborhood. And maybe your kids will know the kids, you will know the parents, etc. Pretty easily could go up to 40-50 homes in such a case. You'd know 1-2 people per family and still be fairly tightly knit.
I would expect that you would need 5-10 acres per family on average, so this would look like 100-200 acres or 200-500 acres. It happens that in the US, 640 acres is used as some notable chunk of land. I'm unsure of what it's called, but it's a very common size.
640 acres is a square mile. So at most, maybe 2.5 miles if you have to zig-zag from one end to the other. So it is a rather large area. If you were to have 50 families, 5 people on average, that'd be 250 people per square mile.
Culberson county averages 0.6 people per square mile. San Francisco is over 18,000 per square mile. Cheyenne, Wyoming is 2,425 people per square mile. So about a tenth the density of Cheyenne could be the target in such a scenario.
Anyway, I'm tired now. Not sure how much sense this will make.