He had a constant inventory of what he called "Divorce Cabins". They were half-finished DIY cabin builds or renovations that turned out to be way more stress and work than the couples expected. This tended to lead to divorce, which lead to a forced sale of the property.
Experienced contractors would pick them up at a discount, finish the work with their crews, and sell them off.
These things are doable if you have infinite time and money to spend on renting the right equipment and hiring help for jobs that require experience and/or multiple people. However, it's virtually impossible for someone to do on weekends alone.