A duplex 2- 2 bed 1 bath, a double wide 3 bed 1 bath, a primary residence 3 bed 2 1/2 bath, and an ADU 3 beds 1 bath.

run down ghetto parks in rural America with beat to crap single wides  are not the same as a park that is full of pit set double wides with pride of ownership and the coachs are all owned by the individuals who paid 50 to 250k each.. or like Orange county or parts of CA were the MH might have sold for 500k or more.. your going to get your space rent with no major issues. 

Based on the market each of these pieces of land with double-wide mobile homes should be around $130,000 a piece based on comps.Has anyone ever done something similar or have expertise they can share around problems I might encounter?

They are essentially high end single wide homes that can be installed and act as an ADU. 

Even if the technology is widely adopted in 10-20 years, there still needs to be government regulation which takes time. 

@Jennifer Lyles great information on the number of rental limitations I never thought of that angle.

So that's why I was approaching it from the other angle. 

Sara Nelson, president of the Association of Flight Attendants union, said airline employees have reported a wide range of troubling incidents.

Assuming all the hoses and drain pipes are hooked up properly, there are two likely problem areas.1) On front load washers there is a wide rubber area in front of the drum. 

Maybe start with photo 2 (wide bedroom shot) as primary.