How do you get into a position after being out of work for a few years and are around 40?

I highly agree with Gagan Singh Rana about learning a new skill. #2 on the (https://www.slideshare.net/linkedin/the-25-skills-that-could-get-you-hired-in-2016) link provided by Gagan is Statistics, which is available on www.khanacademy.org/math/statistics-probability for free. Www.jmp.com/learn/ also has free videos. Statistics is the universal tool that helps all the other disciplines. In combination with your other work experience, it can be differentiating against other applicants.
I myself took a short 2 day class and from then on taught myself additional statistics and Design of Experiments (DoE).

The most valuable statistic tools are t-test, box plots, stepwise regression.

Well, push it. Be yourself and bring out the work experience in everything you do. The age will become a second thought if you strive to outperform the young, not as well rounded, cheaper, millennial crowd. I have the same issue but I fight the good fight and your secret weapon is knowledge. General knowledge and things you learn by working. The young, don't have that. Work ethic. Bring that to the table in spades! Be a machine, personal, over power them and use old traditional techniques to run circles around them. What I mean, personality, charm, hand shakes, quick thumbnail sketches, just be you. Bring it out, your personality and experience. On your CV, don't just list stuff, what did you do at THAT job to make it rock? Today young are missing very basic ingredients and that's your advantage. Good luck

Often times the issue is not your age but finding a good match between your skill sets and open positions.  I encourage you to consider volunteering.  This enables others to view your work efforts and style as well as make new connections.  Others may be willing to recommend or refer you for a position if they develop a personal connection with  you.  Opportunities may exist in church organizations, youth sports, your local chamber of commerce, service organizations.  It would be a way to give back to your community, meet new people and explore new options.  Good luck!

If you're worried about age or the work gap (not saying you are)... let me just say that age is not worth worrying about and is a waste of good energy! You're valuable. Period.

I'm over 40 and consider myself solidly "mid-career" and with so much more ahead. I likely will have a complete career shift at some point and will need to go back to school or pivot by learning a new field by building on the transferable skills I have now. I consider that normal career evolution these days.

One idea... you could play a mental trick on yourself and tell yourself you've left your last job in a different field and want to start a new career track... how would you go about it? Online classes? Reading industry blogs? Entry level "foothold" job in a direction that energizes you? (e.g. If I wanted to open a restaurant, there is no better pivot job than being on the customer service side of food service for a bit... what you learn there will be invaluable as you climb the ladder. And you'd not just be "waiting tables"... you'd be "gathering research" which is entirely different.) Wishing you great luck ahead!

Finding a job over 40 can be a challenge. You have to stand out from the crowd of qualified applicants half your age. Use your assets that come with age. Confidence is an easy attribute that younger applicants can try to fake but should come easy for you. At 40 you know who you are and what you can accomplish. There's no guess work there. I find that interviews are a breeze because I don't feel intimidated because I know there are lots of other options out there.

Also, be picky. Know exactly what you want to do and go for it. Don't settle. There's no time for short changing yourself.

The only things that matter in most industries are your skills and your reputation.
If you've been out of work for a few years, I'd recommend that you develop your skills (i.e. upskill yourself) by getting the skills you need to get a new job. You can use the list here (https://www.slideshare.net/linkedin/the-25-skills-that-could-get-you-hired-in-2016) for the skills most in demand. In order to get these skills, you can Google where you can find these skills - note that EdX, Coursera and Udacity have some great low-priced courses that you can check out.

 When you have been out for a moment, its sometimes can be intimidating so I would recommend to choose something you like to do or passionate about. If you know cooking, go into something culinary so some things are familiar. Be brave to be in love with your 8-5 as you are with your home/family life :)