He has exercise equipment on his patio (very neatly arranged, he is a personal trainer and knows how to do this efficiently and safely). 

What is a typical fee arrangement for running storage units off-site (following technology updates to facilitate this model as best as possible)?

In the meantime, if your parents are planning on moving to TX you may want to just start looking for temporary housing arrangements for them.

It’s a typical college renting arrangement, one kitchen, no locks on doors.

I just can't see the vast majority of working adults wanting to live in a permanent "sleep away" camp-style arrangement. 

I am considering "buying out" the 5 month lease on one of the units... but not sure how to go about this (would this need be an agreement with the Seller who would have to arrange this with the tenant?).

It's getting them to pay on time, dealing with their repair requests, handling disputes and lease violations, arranging lease renewals, and managing move-outs and turnover that will slowly drain your will to live.Here's the point: Every minute you spend trying to be a great PM is a minute spent NOT becoming a great investor.Ask me how I know this...

Please contact me if you have any questions or to arrange a meeting. 

I will definitely need a new house to accomodate this arrangement.

You're only required to arrange accommodation if it’s written in your lease.