I think renter nation is broad, I'm looking at the 25-54 age group.

Your question is way too broad to be answered here, but here is a free course by one of the best in the industry.

I think the increases in those areas will resemble a kind of reverse bell curve, in which cultural values lie at the heart of the urban center on one end of the spectrum, and in the 2 to 50 acre properties which are an hour drive away on the other end. 

The question is where are you offering in this spectrum?

I’m in SoCal but am looking broadly for RE deals.  

As mentioned you would lock in the tax bill on a 721 but it does provide broad diversification and liquidity should that be a goal. 

Also they most likely are made part of the deed and thus is a structure.Prefabricated Home- Again a broad term that would be more in-line with a home manufactured in parts in a factory and shipped in pieces or sections and put together on site, this is more common with commercial buildings that are sometimes engineered and may have different shapes and sizes.

By risk I mean the whole spectrum of possibilities for losing money, from micro to macro.

I have a very specific situation but also a broad question.  

Lots of ink has been spilt from the stories of failure from eminent businesspeople.It's off Broad Street in the SW part of town.