Class C stay indoors, don't answer the door for solicitors, and don't spend a lot of time with neighbors. 

I'm looking to purchase my first property with my fiancé (both 25) with the goal being to establish our primary residence together, as well as giving me the opportunity to add equity/value via rehab before moving on and converting the property into a rental within a year or so to kickstart an investment portfolio.An interesting lead that recently came up is my parent's neighbor's house.

Water is now leaking through the ceiling into my tenant's unit, and it's worsening with every rain also the neighboring unit has sever water damage (like a pool inside and it is owned by the HoA) and water from it leaking very dirty water from the shared wall to mine.

There is such a massive oversupply of units in that region that it will likely affect other neighboring regions for the next few years. 

That's also a next door neighbor as a connection for future development projects he might be interested in investing in.  

A motivated nosey neighbor might try to make an appt to see the property, but in general that doesn't happen too often and agents don't want to waste their time with time-wasters like that.

Doesn't cause trouble for you/neighbors/city/police.That's pretty much the sum of it.

I’ve watched investors lose momentum by sticking to a single city’s slower regulations when a neighboring municipality was more open to new builds.

Like @Collin Hays said, it is being driven more by neighbors tired of poor STR owners not keeping things sorted.We only look for places in vacation areas with a long history of owner driven STRs vs big cities and the like.

Say my neighbor wants to buy a 1 millimeter strip of land along our shared property line for 450k.