Inside the habitat

[Rynn]

I suspect that some of the smaller, earlier ones were quite densely populated. An 'urban' cylinder with lots of layers and lots of habitable space could support a large population, although they might feel a bit cramped. I know I would suffer from claustrophobia in a crowded hab.

People are very adaptable. Tens of millions of people IRL live in dense cities and find it completely fine. To the point that cultural ideas of what a constitutes a large vs small home can be quite different. More dense population also allows for a concentration of services and economy which would be necessary for earlier habs.

Also a crowded urban habitat would need to import food or manufacture it from recycled materials within the hab. But you might get used to it, especially with sophisticated design and social engineering.

With vertical farming, aquaculture, automated polyculture etc. food really shouldn't be a problem. You could have entire decks that are sub-divided into spaces too small for people to walk through upright in order to maximise your growing space

A rural design could grow at least some of its food agriculturally, although I suspect most of the interior would be used for recreational purposes rather than food production. O'Neill's original design incorporated a series of external food production units, collecting sunlight for plant growth in greenhouse habs; a rural habitat would have a lower population, but would still probably need external greenhouse habs to supplement the food supply.

I expect larger environments would be a recreational choice, though another reason might be a desire for a more complex ecosystem. I've no doubt a smaller, denser hab could look very green but the ecosystem would probably be minimally viable in terms of complexity. Something like the Kalpana One concept design.