We do Self storage.  

I recently just sold a 47-unit and 36-unit self-storage deal. 

DSTs function as investment vehicles that hold ownership of income-generating properties, granting investors fractional ownership in various types of commercial real estate such as apartments, self-storage facilities, build-for-rent properties, and NNN (triple net lease) properties.

I always like to put myself in the tenant's shoes.

I'd tell them to stay at a hotel/motel or STR for 3 weeks and put their stuff in storage.

The zoning will define the permitted uses (this will tell you if you can have an RV/Boat storage there) and it will define the density (this will tell you how many tiny homes you can add).You'll want to make sure you don't conflict the existing duplex to a new use or mixed use where you might put the existing use out of compliance. 

If I were in your shoes I would just shop it around.

That would be one major concern for me if I were in your shoes looking to make this decision. 

If you have the storage room, having one of these might be handy for future SC summers, as I'm sure this will happen again at some point.

Has anyone ever used conex / shipping containers as mini storage?