Yeah the property I linked is overpriced but the layout is typical of rowhomes in the city (it is a corner lot which goes for a heftier price tag, but i think you could score a comparable property for $100-125k even in today's ridiculous bull market). In Philadelphia there is definitely a sweet spot between the ultra low end decrepit house that requires a complete tear down/rebuild to meet code and a house that may look aesthetically unpleasing but is structurally sound and easy to get up code. What also appeals to me about this style of house is all of the plumbing is along the back wall, which makes retrofitting alternative plumbing options a bit easier (not sure if city code addresses gray water, but I know rain water harvesting and cisterns are legal). The 2 story rowhomes were all designed for working class families in the early 20th century and are not very popular among contemporary home buyers because they are small with only 1 bathroom (the ones that sell have been re-done with modern decor/amenities and additional bathroom on the ground floor). They are also not large enough to split into multiple units, so real estate investors stay away from them unless they are going to do a complete demolition and build a shiny new multifamily house on the lot. That leaves a sweet spot of opportunity for me on properties that are outdated but not in bad enough shape to justify a full tear down (maybe you can find similar niches in your area?). The city has tax abatements for improvements so I don't have to worry about increasing taxes from appreciation for a few years.
Thanks for the book recommendation, I'll check it out. In terms of energy flow, the obvious easy solution is to tap into the urban waste stream, but of course that's more of a bridge solution as we've talked about in other threads (I'd probably just use it to feed my biogas digester and maybe BSF larvae if I have quite a large setup). In other posts (compost toilet thread), I've brainstormed some ideas of feeding humanure and quail manure to grow BSF larvae and then feeding the harvested larvae to the quail as a closed loop solution. In some ways the ERE homesteader has flexibility because he does not need to generate a large profit by selling his products like a typical farmer, so you can really focus on crops that provide the highest yields (small fish, quail eggs, etc) even if they have no market potential.
I suspect there are personality and political differences at play on bottom-up vs top-down approaches. As an INTJ, the puzzle of optimizing systems within my own boundaries is what appeals to me.