You're going to need some substantial conventional gear experience, and should have a good background working airplanes. Not point to point, but working them.
A maintenance background isn't an absolute requirement, but nearly. You don't need to hold a mechanic certificate, but it's certainly preferred.
You'll need to be certicated through your state ag agency or department. Usually there are up to 6 different tests that must be taken. You'll usually also need to be employed by an operator in order to take the tests. Most operators won't touch you unless you have at least a thousand hours of ag time, as a starting point.
The regional job you just left is an entry level job. Ag work isn't. And it's not easy to break into, either.
Traditionally, one could approach an operator and work a few years mixing chemical, driving tractors, flagging fields, and turning wrenches on the airplane. Over time, the operator would check you out in a super cub or perhaps evena pawnee, assuming you have good flying skills. (A lot of pilots don't). You might be allowed to spray out 25 or 50 gallons of water or tank rinsate here and there. Eventually start doing small bits of insecticide work under supervision. After a bit, you could work into doing herbicide work, and possibly look at larger, more capable airplanes.
You could go buy an airplane, but a lot of farmers won't touch you for business unless you're known for ten or twenty years in their area...and even then, you're still the "new guy."
You might make a fair amount of money, or you might be like a lot of ag drivers who may have earned less in a bad year than you did at your regional in a good year. It can be that bad...or worse.
My first year spraying, we lost a pilot, and all our competitors and neighbors died. How does your wife feel about that?