i have looked into the Landlord locks as mentioned but have not used them. i have one student rental where i use an electronic lock ( that i can control from anywhere, change codes etc.), but the bedrooms are regular keys, as @Jonathan C. mentioned for the front door, the unit is set up to send me an email when the batteries are low. i also have another student rental ( 8 rooms, 2 entry, 2 units + utility room) one master key and each bedroom has its own key that will get students in the entry, there unit, and there own bedroom. had a locksmith do that one. cost me a few hundred dollars with keying and supplying the locks ( 13 total ). i like both setups but may look into the landlord locks again for my 3rd student rental i just purchased.

I paid for the subscription for a few months and drew my own custom Google maps areas and color coded them red/yellow/green based on a "grade" I felt came from a few metrics like crime/average household income/etcI also really like realtors dot com new maps, if you search for an address and click on the map and then go to the top left and choose the Value slider it will give you a nice color coded map of which areas of a neighborhood are higher valued.

Most building codes and HUD standards require bedrooms to have windows for egress and ventilation.

I have had inspectors look at rooms on renovations that were not permitted (we weren't even doing work in the rooms) and asked that certain changes to be made to bring the room up to code (it was minimal).

OKC has alot of opportunity mainly because of its low level of enforcement of housing codes, strong landlord laws and conservative judges in eviction court.

I then called the customer and told them their agent needs an education , of course the deck isnt up to todays code , code changes every year . 

If not try a keyless entry situation that allows you add a temp code that will expire after the work is completed.

@Bryan Zayac  In PA, there is a state document called the Municipal Planning Code MPC. 

#2...not the zoning, although that can be important too, but the actual property code in the Florida statutes about tax liens and the process. 

@Adam AeroI completely agree with @Sofia Komrskova about doing it to code.