Buy them one at a time and keep replicating the model until it stops working.

The problem with the your method of forecasting is that there is literally nothing replicable about it, save for "let historical data be your guide", which you can clearly see is a bad method.

Id appreciate some guidance and possibly to see if theres a good "system" that can be easily replicated.

He uses Behr but I went to Sherwin Williams and they have a Behr paint guide where they can take a Behr paint color and replicate the same color using their Sherwin Williams paint. 

Newbies are often used to some extent by their mentor.So, how can a new investor or operator know what they are being taught and told to do is ethical, legal, reasonably replicated, accepted practice and actually profitable?

Many rentals were previously bank REOs or foreclosures from owners who didn't understand the financial & operational aspects.This would be hard to replicate elsewhere, as Gatlinburg is focused on year round tourism which is great for low vacancy.  

My initial investment was just under 100k and your 400 can easily replicate the experiences IF YOU CHOOSE WELL.

Seriously, replicate those returns and youll make yourself and your friends wealthy.  

These types of buildings have a certain character that is really expensive to replicate with moldings and old style flooring etc.  

Remember, CoStar comps is updated by brokers themselves, other places like REIS have a staff of around 100 people who try and do this data themselves which is impossible to replicate CoStars superiority when it's updated daily by thousands of brokers in the market.