On top of that, adding furniture to those rooms and doing MTR rooms will increase that even more but does require more work.

With a 3 bedroom house, moving all of that furniture again is not something renters take lightly.  

If the rent is $1600/month and your furniture really does only cost $5,000, you are only on the hook for $24,200 if you get 0 renters for the whole year, which is unlikely.

Overgrown yards, cars and tires in yards, backyards with furniture and trash. 

With this (awful) approach of pretty much just listing a house on these sites....and hoping for the best, my prediction is you would get pretty much slaughtered in the reviews, which would lead to less bookings, and then eventually reaching the conclusion that STRs don't work.To do it with a better degree of success you would want to purchase the property, put in all the finishing touches that guests want to see such as books about the area, maps, buy new furniture and decor if needed, create a welcome book with recommendations on restaurants and attractions, list it on multiple sites, build your own website/brand, promote it on social media platforms, have professional pictures taken, have your listing completely filled out, be incredibly responsive to every question and message you receive, build a really good guidebook to the point where you are almost an ambassador/tour guide for the area, interview and contract with professional cleaners and have backup cleaners in place, have a relationship with a professional handyperson so they know who you are when you call the first time requesting their service, have several electrical and plumbing contractors identified to call when problems come up, set expectations for your cleaners up front and provide feedback immediately to them when guests have a complaint, and handle all complaints with your guests the way you would want it handled if you were the guest...put the guest first before any profit/money. 

These floors are damaged as soon as the movers bring the furniture in the house because they are essentially press-board with a coating on the top.

We left all of the furniture so it is ready to go.

you don't see me going to the furniture store and saying "I need this 450 couch but can pay just $150".

With furniture, decor, etc added in...it was about a $350,000 purchase to get into the nice rental that it is today.

The place is furnished w/staging furniture and rugs, so it is a close approximate.