I'm assuming IT professionals and the like, accustomed to making $100,000+ aren't taking jobs in fast food or for $10 / hour working retail to make part time money ($10/hr doesn't get you anywhere close to $30,000 / year anyway).
For the past 3 years, I have worked 500 - 800 hours a year as a electronics engineering consultant (really a specialized computer hardware hacker) maintaining and updating systems I developed 5-10 years ago. It's definitely "trailing edge technology" being used to support the entertainment industry.
Overall, I net about twice the figure you mentioned, and I expect this opportunity will sunset in the next year. Being self employed, I have been able to contribute a substantial amount of the earnings to a solo 401K to counter the impact of having to pay self employment tax.
I have been FI for over five years, and this income is approximately twice my annual expenses. Financially, this has shifted me to a target of a 3% SWR, which may be wiser given the current point in the business cycle.
Health insurance does remain a concern. Before the ACA I would sometime work as a W2 employee with benefits to have access to plans through COBRA. If the current Congress manages to crash the ACA markets, I may need to consider a part time job solely for the access to reasonable health insurance rates.