At the same time I feel people don't understand that the markup of GCs material most of the time comes out to the same cost as you would go buying it yourself.

So that is a cost as well.      

It must cost a fortune since they want you to call. 

Lending on any property that is or will become owner occupied might be something you will want to stay away from as you will most likely trigger licensing as well as Section 32 (high cost). A

That’s why you see cabins an hour west of Charlotte cost a third of the price as the same type of cabin on the TN side of the Smokies.Now sure ROI is a numerator/denominator game that includes revenue and purchase price, and if all the best locations were priced higher than the potential additional return they give then that doesn’t move the needle.

I'd also like the desk cost as low as possible. 

It will cost a lot of money, but you will see how things are done correctly.

I think the BP bookstore has some books on estimating rehab cost as well.  

The secret is understanding the meaning, and the impact of this number sequence, and applying it to every decision you make as a REI.                                                                        1073741824Buy with as little cash (that's your cost) as possible.

The qualifications are way easier than Fannie/Freddie loans, but cost a little more.