This arrangement had the benefit of ease of operation, permits, construction management, listing and sale.

They buy land, permit it, and sell it.

My favorite tip to newcomers is to set up key word alerts to find out about topics and geographies that interest you.  

Zoning concerns, legal/permit costs? 

The realtor was quick to tell me that it was done "to code" but that it was done with no permits so not listed in the total square footage.When I went outside, I noticed that the add-on outer wall was 3 feet from the property fence on the side of the home.  

Hire out the major work if you're not qualified and/or it requires permits, but little things like cosmetic upgrades are pretty easy with youtube instructional videos. 

That number also includes all utilities (which the water is very expensive for me because we couldn't dig a well), county permit fees, and financing costs.But like @Rob Beland said, every project is completely unique and the numbers can be drastically different. 

I said that tax lien, foreclosure and other types of auctions seem interesting and are a topic I'd like to try to figure out.He said that in Denver, there is a group of investors (about 20 or 30 of them, he thinks) that have pretty much locked any new-comers completely out of that niche.When auction lists come out, they go through it and they decide which of them will get what.  

I do like that I can now easily go pull permits and simply tell the building department who my subs will be.

The solution typically requires removal down to a solid base but I usually end up having to remove old stucco, re-wrap wire and paper after pulling permits, then scratch coat, brown fiat and color coats are applied.