If you want to physically own the doors than going to a larger multifamily, Triple net lease, mobile homes, storage units would be the way to go. 

That is what we use at our STR and our home with no issue.The Yale assure is a mesh device that needs a wifi bridge.

ALL THE ATTICS HAVE EASY ACESS, WALKING/STORAGE.

by renovating the units like kitchen ,bathrooms and rooms , adding sq ft to the bathroom also adding more rooms , finishing my basement and remodeling the attic for extra storage What was the outcome?

At that point, I choose how to dispose of the items (trash, sell, storage, etc)Question: what, exactly, was left behind?

I say generally because there is a sound argument. out there that a house on a farm can be included as part of the investment property since the farmer or farm hands have to be on site (just like a self storage apt, or a managers unit in an apt building). 

I apologize in advance if this is the wrong area to post this question in, I am still finding my way around the site.Last year I found a 5 unit property that was marketed as a fourplex with "garage storage".

I store them in a Google drive, but I have a business account with unlimited storage.

Any type of storage for vehicles such as boats or RVs if zoned appropriately.

Completely renovated the entire house to increase estimated rent and home value; this included luxury vinyl planks for flooring on main floor and basement, fresh paint throughout, new carpeting on the second floor, remodeled all bathrooms, added a shed for storage in the backyard (it's a townhouse, space is crucial in the area!)