Try contacting a local business about paying them for a mail drop (self storage facility, law office, real estate broker).

Thought, with minimal clean up, maybe I could rent out to peeps for storage.

You could try the Neighbor storage app.

I would like to level up and learn more about investing in commercial properties (apartments, self-storage, senior living facilities etc.).

But they also kept the old one to park their vehicles & apparently use it for storage & sorting

The exception is if you're running what essentially amounts to a hotel or motel, running a parking lot, or running a storage facility/warehouse.Real estate is also generally "per se" passive and subject to the passive activity loss rules unless you are an RE pro.Your returns should be amended for the tax years with open statute of limitations. 

In my case, I have residential rentals in one LLC, commercial properties in another, self storage in a third, and my real estate company operates in a fourth.

I use cozy.co for my rental houses and also for my storage units. 

(Think if you just fill in all that storage how someone down or upstream would be affected).Happy to connect if you want to take a deeper look into it and explore options!

I'm in the process of developing my first RV park (full-time living) and RV storage facility from the ground up in the Austin area.