Air Flow - There is a window in the room and I have been advised that an AC unit can be added to this to keep the room cool 2.

The air conditioner was stolen awhile back. 

This is commonly accomplished by adding "approved" material(s), detailed in the building code, to contain air flow.

However, I do get calls for major plumbing repairs, air conditioners, and hurricane damage - hence the need to factor in maintenance.

The only issue I had is that the inspector left the air conditioning at a low setting of 70 degrees. 

I would list it on Air BnB and VRBO first and coordinate calendars.

While moving out walk-through he updated landlord and suggested to service Air Conditioning unit since compressor was not working.

Kensington is a rough, open air drug market these days.

If I were doing this, I would definitely go with an air-impermeable spray foam -- sprayed tight to the underside of the roof sheathing to the thickness required to get the code R-value. 

I don't think this thought came out of thin air.