A couple of things. If you are planning to ER or semi-ER from your professions in your late 30s, what were you thinking about how you wanted to spend your remaining decades? Is there another hobby or "occupation" (as in occupation of your time, not necessarily a job) that you were hoping to spend more time enjoying? (It doesn't sound like you were thinking of real estate this way.)
If so, look at these next few years as a time to gain skills that will help you to hit the ground running when you're ready to move. Find an entry-level job in that field, even if you don't plan to actually have a new career in it, just to learn some skills. Or, get a low-stress, part-time job and start giving lessons just to make some cash to save over these next few years, develop your teaching skills, and spend your down-time doing the self-work that will help you to figure out what you'd like to do next.
Personally, I wouldn't consider farming as a new option. You'll be putting in long hours for very low pay for a number of years, and if you're headed to CA or somewhere similar, you'll be looking at land prices that make it tough to pull in much income. Nothing wrong with farming for passion, and it is possible to earn a modest living once you've figured out how to optimize (this can take some years), but it's a steep learning curve and low pay for a lot of labour; often you're very lucky just to eat for free and break even on the rest of your costs. In our (high land price) area, (very) full-time farmers typically gross $100,000, but only come out ahead by about $30K. And that's full-on work, including managing interns and staff, contracting with restaurants, delivering CSAs, etc in a place with a wealthy foodie population and a long growing season. Hobby farmers break even or do it to keep their own living and food expenses low.
But again, if you're in MO, there will be farms where you could intern or work to get a better sense of whether you've got the passion to make the numbers worth it for you.
If I were in your shoes, I would be saving as much $ as possible right now, while your wife is still working (ie get your living costs down as low as possible and consider this your big push for short term max saving), then pick a place to move that has as low a COL as you can stand (in the area you want to be) while still having a rental market. Then I would look for a fixer-upper home that you were allowed to build the "laneway" house or cottage on (rather than building a more expensive house and cottage)--you might also find something already purpose built; we see this configuration pretty regularly out here. Then I would have you and your wife each work part-time doing lessons or whatever and try to live on this income + the rental income while letting your stash grow in the background.
Keep it simple! If you could get $1000/mo rent from a cottage, and pull in another $1000-$1500 from lessons between you, some other petty cash from the occasional side-gigs or another hobby, you could be close to $3000/mo, which can be pretty comfortable without a mortgage. But it sounds like it might be a simpler life than what you have in mind...
(Just for reference, our plan shortly is to have no mortgage, move to a larger acreage where DH will manage the property and earn a small income from it--maybe $5-10K/year--and work part-time. I will continue working full-time for another 15 or so years, partly to earn a very nice pension. We estimate our living expenses at about $40K (Canadian), but that includes a small sailboat and assumes that DH's small income will cover all farming and property expenses. We're older than you and DH will draw SS in less than 10 yrs. So my income will cover living expenses and savings; his will cover everything else. In about 15 yrs, my pension+both our SS will cover us comfortably. It's a simple life, but an awesome one.)
Good luck; I love hearing FI stories from musicians and artists, and I went to school in MO many years ago...look forward to following your story.
