Most suggest blown in insulation in attic and walls, remove old from attic, cut holes in drywall/patch/texture/paint. 

I mean there are units I have seen that have leaks, huge holes in the walls, even feces in the floor and infested with roaches.

If that’s what it is you can remove it to give you a spot to taper in the joint compound to the existing ceiling after you’ve filled the hole made by the top 2x4 with proper sized Sheetrock.

@Kenneth Freire I did Bnb for a few years and I would definitely keep things as a long term rental.Bnb you need a hole team and what not to keep making money and if that team is messed with then you stop making money.To me I don't think it's worth the work compared to long term rentals.

The GOAL of this thread is for you to poke holes in my strategy and tell me WHY this couldn't work.

The previous owner has someone living in 1 of the properties in unlivable conditions (the back room is 2x4's with holes in the prop).

Good luck.If possible, I would keep the putting green, a three hole course and the walking path, jus for kicks. 

My attitude right now is as long as the property is left as it was when we turned it over the them originally and its ready to go for the next tenants, everything cleaned up, no animal scratches, holes in the carpet, bad smells, picture holes painted, carpet cleaned, oven, refrigerator, etc., then I don't really care. 

My family and I are living in a real sh** hole, working our butts off to fix it up.

Depending how long the previous tenant was there, replace carbons/smokes, furnace filter and (maybe) furnace cleaning, fire extinguisher, touch up paint/nail holes, fireplace cleaning (if applicable), dryer vent clean-out, if it's an older property possibly do a roto-rooter service of the main line.