With all of the accessories and elecrical, it cost me about $2500 delivered. 

I like the Schlage Lever locks for most applications which can last nearly a year with one set of batteries.As a general rule, be careful or have local help on hand if using any of the WiFi based locks: WiFi-based locks use much more power than locks that interact with an intermediary hub or plug-in accessory, since those locks are most often lower energy Bluetooth at the lock and the hubs just stay plugged into the wall.  

FNMA Appraisal Guidelines for 2-4 Unit properties require “The building sketch shall include all completed levels above grade within the dwelling, all basement area (both finished and unfinished) and any finished living areas that were not included in gross living area, but were given value by the appraiser, such as detached accessory units, carriage houses, living area above detached garages/barns, pool houses, game rooms, studios, etc. · A floor plan/building sketch with exterior dimensions is required on all transactions. · If the floor plan is atypical or functionally obsolete, thus limiting the market appeal for the property in comparison to competitive properties in the neighborhood, a detailed floor plan sketch showing interior walls, doors, and interior dimensions is required. · The appraiser must also include calculations to show how they arrived at the estimate for gross building area.”Okay, that is long enough.

The ADU is often treated like an accessory like pool, Solar, well, non-unit out buildings.  

It's not one single family but rather 2 single families each with an accessory dwelling unit (ADU) or mother in law suite.

In some estate in the West such as CA, WA, there are specific rules and overall, it is allowed to rent out a guesthouse (or ADU - Accessory Dwelling Units).

I vow to never let a tenant control me like this again.I never allow vaping or smoking of anything anywhere on the property so the cigarette butts would also be an immediate eviction. 

I'd start with a place where I could live in one unit and rent the other-not a duplex, but a house with a suite or accessory unit. 

They're one of the biggest leaders of accessory dwelling units here in Denver.

Under the long-existing Denver STR rules, if your carriage house is truly an accessory dwelling unit, and was either permitted under current Denver zoning codes, or was grandfathered because it was built prior to current zoning ordinances, then you are totally allowed to do Airbnb and short-term rentals in it.