Your friend had a simple solution to the problem in front of him that could have been solved in 5 minutes, made himself $60k and served the interest of his client.  

I listened to the podcast and it led me to another source and a solution.

Does anyone have any ideas for a cheap, potentially DIY solution for a ground cover or pavement?

Is there anyone who knows of a more cost effective solution?

I used a local broker and landed on American Modern.  

Maybe into white trim, just basic modernization that the appraiser is going want to see to up its value without getting too buried in rehab costs.  

These are complex homes built to the California Building Standards Code that require installation and finishing to meet the regular California Building Code.Pedro's solution of trying to contact the manufacturers directlyThe manufacturers of modular homes (almost as a rule) don't sell directly to homeowners, so this is really a pointless loop that he is sending you on. 

Best solution to cat pee I am aware of.

Anyone have a better tech solution? 

If we file for a variance, it will allow us 15', but is not for sure, and will be time consuming and costly. 13' is a given.After looking at lots of small modern homes online, I believe we can fit a nice, modern "tiny home" on this lot (like the one attached) and sell for a profit and leave the stream buffer as is.