I want to reach out and get feedback on where I would be able to find off market self storage facilities and how to approach the owner?

Many DSCR programs require an investor to have a mortgage history- there are some DSCR mortgage programs that will work with investors who are renting- some refer to them as first time home buyers (FTHBs)- DSCR loans are only for investment properties where the owner isn't living there. 

Owner occupied united increased by 8.4%"Still, although the overall share of households that rented decreased, the number of rented units increased by over a million units (43.3 million to 44.6 million)."

Would I go to the current owners bank to see if they would allow a subject to loan? 

The 10 acres are about 90% planted pine (the previous owner planted it).

Thus, they will contact every owner they can that has a rental being advertised, hoping the owner is tired and just wants to dump a headache of a property for 60-70% of market value.

I had not heard of the corporate housing by owner site.

Quote from @Fernando Martin-Gullans: Hey y’all, I’m a retail investor with 2 SFH rentals worth a combined ~$650k looking to utilize some of my stored equity to buy more out-of-state properties, but I’m not quite sure how best to proceed given that my interest rates are incredibly low (leaning me away from refinancing) and neither property is owner-occupied (which I believe prevents me from using a HELOC).

If my spouse wasn’t opposed to moving I would try to buy a new house hack every 12-15 months and use low down payment owner occupied loans for as long as it made sense.

One with low cash, one with some owner financing and a little less price.