And boom you buy a lot for the price of a single lot and with some simple forms to the city you get to re establish the old lots..

Sometimes even 7 or 8% lenders are had to find for 3 or 5 years much less for 15 or 30 years. exactlybut im sure its possible because people are doing it Possible yes, but there are a lot of complexities and moving pieces - this is generally the lending business model, not a simple "arbitrage" glitch or easy scheme..

At its core property management is simple though.

I've been in this situation a billion times- honestly, the answer is very simple.

I am the only real estate investor with my bookkeeper and at first she thought this was a little overboard but once she started setting rules in Quickbooks to simplify her work she quickly realized how simple this method makes things.

Keep it simple is great advice.

I don’t have an STR myself but have helped a friend set up and manage a couple last year and it’s not as simple as it used to be. 

In my case it was not as simple as wake up and do it.  

Can I still do simple 4 box calculation? 

Either you messed up the numbers, which it’s a rather simple calc so I hope not.