It's beautiful...a dozen fishing cabins in Northern Minnesota on an entire peninsula of a lake surrounded by state forest land.  

I work for a small but mighty management company owned and operated by veterans.

That said, I know a few MHP operators that make some pretty tremendous money on the trailers, mostly by renting to people who need to pay in cash and have someone not ask a lot of questions - illegal/undocumented immigrants, transients, probably some criminals for sure, sometimes people (mostly women) hiding from domestic abusers, etc.

On the flip side, having more choice in location with an existing product could be advantageous to both his personal life and the earnings potential; add in the second unit having the potential of being a STR/MTR and location becomes even more important.The contract/permit side CAN be challenging location by location; assuming he's working with someone who knows what they're doing, Raleigh makes it easier to get permits for these larger "small scale" projects than Durham.

But the damage caused by hanging them (namely puddying the holes and touch up paint, or repainting walls if touching up doesn't work) will come out of their deposit. 

By owner or by a broker?  

In my acquaintance's experience, one of whom has triple digit number of loans being serviced by them they have produced quality and reliable results.FCI is another large, well known servicer used by many people in the industry.

It is neither audio nor ebook but a hard copy book, Real Estate by Number in my case.

If you're able to, start networking at local Milwaukee real estate meetups---this is the very best education and inspiration that you will ever find--I started real estate by signing up for a guru program but by far, my best education came from speaking to other active local investors who are actually doing deals or have built financial freedom---the nationwide guru program only taught about flips and rentals but there are so many different strategies that locals have and are successfully doing.

I recently read Cheap Dirt by Beaux Blast and the book inspired me to learn more.