It also has some shark tanks, but those are pretty obvious to figure out. 

The home is small and old but everything is working as far as water (public), septic tank, stove, electric, etc.It does look outdated though (and in my opinion ugly), so I’m thinking of perhaps replace it with another used mobile home that’s in good condition and built at least in the 90s.My plan is to live there and flip it after a year or so.

It's on public water and septic tank. 

Finally, if you have a septic tank, you do not want a disposal of any kind. 

Next week the 3 underground tanks are getting removed, soils tested, and if cleared for phase 1 or 2 then backfilled.

Personally I think you could sell that.Another option might be to go on something like Shark Tank or really hit hard the small business VC/Angel/Startup type circuit and see if you could raise funds there. 

I’ve been browsing Paperstac quite a bit lately, but I’ve noticed that most of the properties against which the notes are secured are decrepit shacks located in very rural areas.I’m fully aware that the kind of borrower who defaults on their mortgage won’t usually be living in an ornate mansion, but do you know of any way to buy notes for properties located in major cities, or at least somewhere where home values won’t tank 50% when the local chicken slaughterhouse or glue factory closes?

In essence, water enters the sealed septic tank, solids are separated, and the water then moves to the porous leach fields for ground absorption.

Second, if you have septic versus sewer, you need to see what the septic tank is rated for.

Your CAP rate will be dangerously inaccurate if you calculate expenses incorrectly so let's break those down.Utility Set-up- As an overview you need to know the difference  between city-provided utilities and onsite such as Septic Tanks with Leech fields, lagoons, Wells, EtcGetting more specific what utilities are maintained by the community, paid by the community vs the tenants.I will give you a quick example, I own a park with a bunch of multifamily manufactured units of which I pay the electricity bill.