The past tenant was a hoarder and the apartment has not been lived in or touched since 1999 (26 years)! 

All the water issues could have caused this as well.

Quote from @Kornelius Friske: We have a STR located in peoria AZ. it's 6 beds (garage conversion) and about 3900 sq ft in total. our energy bill last month was $450 and has been hovering in the $350-$450 range since we went live in august.

The only reason I recommend focusing on a couple neighborhoods, is because house hacking entails buying in a neighborhood you want to live in.  

I currently live in Wilmington, NC, so Birmingham would be about an 8-hour drive for me.

For example it is my understanding that Big Bear allows it but whoever is managing the property has to live within 1 hour of the property. 

I've lived in central Texas for 44 years and never have I replaced a roof less than 20 years old.

Some areas have restrictions on mobile homes or rentals.Utilities: Ensure the land is equipped with essential utilities like water, sewer, and electricity.

I recently purchased my first duplex in Peoria, AZ in September and I am using it as a house hack where I rent out one side and live in the other.

From there mechanical and large items are my first priority (water heater, HVAC, roof) - though an inspection gives us more information and those items can be used as great negotiation tools during your due diligence period.