The  GM criteria must match with the Micro-Market Financial Profile (cost of entrance and return upon exit) and strategy I use to execute a "connection" between the two within that market. 

Our location was 14 miles from the Utah Trail entrance to Joshua Tree and we had an outdoor shower and two porta-potties.

So now the beam is about 2" below the doorway entrance making an odd entry beam lower than the entry door.

Right after that I bricked up all the entrances/exits.

If you eliminated that entrance in the right you could get a large peninsula in there.  

Build in such a way that for right now the master is separate (with its own entrance) for Airbnb purposes but able to poke a hole for a door to the main house down the line for future buyers.

While I do see the potential benefit of marketing it to renters as a possible "duplex with separate entrances" or an apartment with extra rec room / storage space, I'm concerned with possible C of O issues.  

I would recommend you use a conservative cap rate of 1.5% higher than your entrance cap rate.

Here's an update:  I have an exterior door off the kitchen for our Out-of-state STR that is the preferred exit/entrance for the house. 

We’re going through the written appraisal and there are many errors (for example it says there’s only one attic with a scuttle entrance when there are two attics and each has pull down stairs).