So our goal is to acquire the home/office addresses for owners of facilities in order to insure they see our mailers.My methodology so far has been to go county by county, identify all self storage facilities on Google Maps (double-checking with our database to make sure I don't miss any not on Google,) and entering the addresses into a tax parcel GIS unique to the county.

and sometimes I'm not the most practical person in my methodology.  

Get your screening methodology in place.   

Some ways to diversify in real estate of course can be by location, asset-type, methodology (syndication, joint-venture, sole-ownership), etc.Example :  If an investor invests into a syndication fund that invests into self-storage, mobile home parks and multifamily.

Roofstock suggests 29 submarkets, based on input from their network of property managers.  A bit of a marketing piece, certainly, but value-added IMO, and not only are the submarkets worth having a look at, but also r...

Any insight would be appreciated - your methodology on your first deal would be helpful as well. 

It's all about the methodology.

I would urge you to learn how the methodology of the calculator works before you just start using it.Unfortunately it's not just as simple as the 2% rule or the 50% rule or we'd all be rich ;).

Anyone else have any other methodology or source? 

You don't state your methodology, but in your article your #1 and #2 top appreciation cities are not in the top 100 in size per https://worldpopulationreview.com/us-cities which means you mix and match (IMO) non-comparable cities.