I converted our garage into an Accessory Dwelling Unit.

In general you should start looking for a single family house that has zoning regulations that allows to ADU (Accessory Dwelling Unit) or can be setup to house hack. 

My wife an I use it when we travel almost exclusively (she currently is staying in one in SAC while she is taking a class), and have friends and clients in Portland who have ADU (granny flats, accessory dwelling units) and rooms that they rent that pay their mortgage and LOVE it.In terms of using it to increase your RE holdings the only issue I have been running into is not being able to qualify using the short term rental income.  

@Lori Spadaro - I would recommend avoiding Boulder for Airbnb right now unless you can get a property with an accessory dwelling unit and you can put the main home as your permanent address.

I've done some research on Accessory Dwelling Units as well. 

Great way to recognize an opportunity to add value, I love accessory dwellings!

Our City allows you to build what they call Accessory Dwelling Units in backyards!

I called on retail bicycle stores to sell them bicycle parts and accessories.

Also, I know HomeReady allows you to use gross rent from the ADU (Accessory Dwelling Unit) to help qualify for the mortgage as well, I'm not 100% sure about the HomePossible loan.  

Some people would rather watch TV, vape, drive a fancy vehicle, wear $300 sneakers, and complain about how the man is keeping them down.