For example, did he buy a business vehicle that he depreciates on his taxes over time?

Some people take signings for $35 thinking they are making money but don't because they don't account for vehicle expenses, paper, toner, etc.After expenses, your profit only comes out to like $10/hour or so on most days because packages are upwards of 250 pages and you have to print two of them.

Modular is a similar but never an actual vehicle by DMV standards. 

If I purchase the investment property in my retirement account, I can't do the work myself - I have to hire out and pay contractors through the retirement vehicle.

There are however different vehicles and scenarios that may help achieve your goalsHope this helps!

The basics can be summed up as follows: borrow max available secured by the acquisitions fixed assets; sell the acquisitions receivables to a factor; mortgage any real property the acquisition owns; sell preferred stock and bonds in the acquisition vehicle to family, friends and associates; and obtain seller financing for the balance plus working capital from the seller.  

The only debt I have is what I owe on my current vehicle.

If you lose your home, apartment and or vehicle move in with your parents no matter how old you are or how old they are.

The neighbor keeps threatening to move the privacy fence over several feet onto the driveway, which allows vehicle access to the parking area at the back of the house.

I do believe there is merit in following simple best practices that have asset protection as a side benefit:  1) Taking out large mortgages on properties to minimize equity; 2) Having adequate liability insurance; 3) Contributing assets to retirement plans and other protected vehicles; 4) Dividing ownership of family assets between yourself, your spouse, and your children; and, especially, 5) Running an honest business and treating people fairly.