Regarding downsides, or perhaps good barriers to entry, saturation is pretty strong, good help is quite hard to come by, inventory has been hovering around 25 or so homes for a while (most of which are not STR material), and much of the recent cabin listings have been grossly overpriced.

.$30/board should cover all labor and all materials...

This is pretty much how banks do things too - the idea is that not only do you have to afford your rent - but also your electric, your food, your car, your insurance, your gas, internet, etc.  

When I do, I use a written agreement that explains specifically what they will do, who pays for what, the materials to be used, a completion date, etc.

The Internet, social media, will repeat information. 

As you have experienced, trying to predict what will happen through the course of two years is very difficult - contractor integrity, materials costs, what the sale price will be, what the rental price will be. 

This includes construction, materials, labor, permits, and any other associated costs.Negotiate TI Allowance:Landlord and tenant negotiate the TI allowance amount based on the estimated total cost of improvements.

While I agree with @Nathan Gesner with the idea of reading other material, I will say the networking aspect of the 3-day event is unmatched.

Hi, I'm new to realestate so I'm devouring learning material.

I would go with someone local, someone you know, someone who is honest and trustworthy, someone who knows what they are doing, rather than a big name you saw on the internet.