What your are asking about should be an automated system in their company.

If I build two 4-plexs (townhouse style) per 21,400 SF, I don't need to have a sprinkler system.

Agree with above, but start building your processes and systems and you'll be fine.

Regarding the private sewage, my understanding is it is a septic system with a drain field that is located across from the park.

There was 2004 remodel that updated mechanical, electrical and sprinkler systems.

All systems are a go... except financing.

I've put almost $25,000 into the house with a major repair for the well water system. 

Hey BP,I’m managing 4 units for a distance and am trying figure out the best system or solution to the keys.My first thought is to have a boots on the ground person I can trust to collect keys and take pics of units when tenant leaves.

Another argument (iirc) is that if you're not using an auto-dialing system, it doesn't apply.Don't take my word on all of this, though. 

This could range anywhere from full on online systems/dashboards to as simple as electronic door locks.