The laws of Sacramento county are pretty strict when it comes to STR, they state: "The short-term rental must remain an accessory use to your full-time occupancy. 

Five bills made effective on January 1, 2020 have significantly streamlined the ADU construction and approval process.Plus: The budget agreement (enacted June 27th 2023) restores $50 million for the California Housing Finance Agency’s ADU Grant Program, which provides up to $40,000 to help cover the planning and permitting costs involved in an accessory dwelling unit.- BP thread relating to your question: https://www.biggerpockets.com/...- LA County has multiple different cities with different RSOs, so this will really depend.

I'd really appreciate your insights on this.The property consists of three homes: two legally habitable, and one accessory dwelling unit (ADU) not permitted for living.

Instead, I'd plan to either invest the money and just let it grow so that when I retire, I can pay off this house or I'll use the cash to build accessory dwelling units on my four other rental properties.

No dice here though because Roseville does not allow accessory dwelling units (mother-in-law suites count for this as well as walkout basements) to be rented for anything less than 30 days. 

You got your answer more than once - use comps for a 2-unit, BUT i'll just add that if you are looking to get started and cashflow is more important than paying over a 2-unit comp price may not be the worst idea.I'd also double-check to see if the unit happens to be in Chicago's pilot accessory dwelling unit (ADU) area....if so then you could legally convert a unit.Lastly, it might be worth doing some zoning calculations to see how many units you could have by right, so that in the future if you wanted to you could re-zone to more units if you had the square footage.

Your goals and story: My wife and I want to grow a rental portfolio in Colorado.Type of property: Single family (preferably with accessory dwellings / carriage houses)Location of property: Colorado SpringsPurpose of financing: PurchaseType of financing sought: Preferably conventional since we don't have a big complicated portfolio yet.

In my area these carriage houses, detached apartments, Detached Accessory Units, are sold and marketed including these units. 

Do some research on local zoning regulations and explore possibilities for accessory dwelling units. 

An accessory dwelling unit shall be located in a principal dwelling unit that is located on a lot of at least 14,000 square feet.