Slate's Explainer on Cost-Benefit Analysis of the Proposed New ADA Regs

See this piece, which begins:

The Department of Justice is set to propose new rules on Tuesday that would make it easier for people with disabilities to move around public places like office buildings, swimming pools, and miniature-golf courses. According to a government estimate, the changes would cost $23 billion but provide $54 billion in public benefits. How do you calculate the benefits of getting around a miniature golf course?