Ask HN: How can I gain more control over how much I work?

I have 12 years experience writing software. The first half of that was at big data startup working with distributed systems using C++ and python. The second half has been more conventional full-stack development. That would be node / react / angular / backbone, etc. I was recently a part of a team upgrading a legacy system to a modern web application.

I do enjoy my job and software in general, but there are a lot of other things I'd like to do in life and having a full-time job makes that difficult. Here are some options I've considered and my thoughts about them.

1) Contract work: I live in NYC. From what I gather online, most contract opportunities are actually just a way for companies to put you on probation for a year before hiring you. I would happily work for 6 months to a year to then be able to take 1-3 months off. I can't help but wonder if there aren't speciality developers work shorter contracts that aren't just glorified probation. Am I missing something here?

2) Part-time work: Another option I'd considered would be part-time work. If I worked two to three days a week I think I would have enough time. But I really don't see this anywhere. Have any of you guys negotiated a full-time down to part-time?

3) Freelance work: This might be ideal. Given a large enough rainy-day fund and a stream of work I could take time off between projects. I also am attracted to the challenge as well. But I don't know how to find work. And the work that I see on upwork, etc. seems to be simple websites that others can do more cheaply. Where can I find freelance work for my skills? I'd love the idea of working on a C++ codebase to fix some issue. Does anyone have any advice on what sort of work I ought to be looking for given my experience and where / how I should be looking? Cold-calling perhaps?

4) Something else? I feel like my motivation and end-goal are pretty obvious here. Is there some other way I can achieve my goal that I haven't been considering?