And, that code could be entered into the device at the entry door which would unlock the door allowing access to their rental.

There are lots of spaces within CRE (retail, industrial, office, multifamily, self-storage, leisure, healthcare, etc.) and retail has definitely and will continue to be impacted by the internet.Malls are changing to the indoor/outdoor type with mixed use (retail, residential, leisure, office all combined) and entertainment included. 

I thought of setting a storage container on a lot and offering it for storage, for a fee.

Google actually has a large data storage facility in the area, plus there is a fiber optic cable manufacturer that produces the most fiber optic cable in the eastern US. 

Over the next few years, I'm going to be putting 10 more homes in the park with the goal to sell when it's "maximized" (positioning it as a nice double wide community, not a sardine can storage shelf).

Years ago I use to go to storage shed auctions before they made tv shows about it , made lots of great scores .  

Unless there’s an opportunity to improve the building, add revenue via things like laundry/storage, get concessions from the seller this one doesn’t look to attractive.

Everything to 'the curb' (actually to a reasonably secure storage area). 

First big deal and it's a quad Plex with 30 storage units.2x 2/1 units - $900/mo2x 1/1 units - $700/mo2016 gross/net - $32,800/$18,3352017 gross/net - $30,100/$14,677Storage units vary in price but total revenue was:2016 - $10,8732017 - $9,177Asking price is $350,000 and cap appears to be 11+%.

Don't forget there are often highly leveragable points in a transaction where you can create a ton of value (e.g. paying to for yard care, cleaning the place up, moving stuff out the house and placing in storage, paying for little things that have a huge impact) as well that you can create big value with e.g. for every dollar you put in you get out $20.