Courtesy of John S, Blue Ribbon Eggs, Franklin, NC
The single most important thing you said was, "We really need to start bringing in an income as work around here is slim pickins." If you need income don't spend capital.
What you need is some reasonably good ground, a strong tiller, a simple watering system, seed, a canopy and table for the market (that is used for your processing center during harvest) and if you have any extra, a cooler storage system (walk-in, convinience store drink cooler, used fridge).
Soil Amendments - If you don't do a soil test, how do you know what your ground needs? Maybe nothing! Don't guess. Talk to your county ag agent. Our state does it free (in small amounts) for the citizens with a full chemical analysis. My agent makes recommendations based upon the growing 'style'-organic in my case.
Soil temperature is important too. I start my early spring plantings at 35+degree soil (spinach, lettuce and onions) 40+ degree soil (peas, radishes, turnips, broccoli, beets and cauliflower) and a strong probability that air temperatures won't fall below 25 degrees F in the future. (late Feb, early March around here. ZONE 6B/7A). If they freeze out I replant, but with the mixed blessing of climate change it's unlikely.
Look for free stuff. I have tracked down guys picking up leaves (when I lived in town) and if my yard was closer than the dump I'd get them to dump the leaves in my yard (they got paid by the load or the mile). Now when the highway department is chipping downed trees on roadways I chat up the fellas and often they'll just drop it in the yard for me. It's the good ol' boy network, and it works for girls too. Tips are often appreciated and a ten or twenty won't offend most.
Tunnels, hoop houses, tents, tee pees etc.- wait a bit. Perhaps you might want to buy those items later, but you can do it from your profits. Personally, I find them too much trouble. I prefer to spend my winter getting fat on all the food I raised.
Ditto for driving to remote acreage. Find the ground closest to your back door, till'er up and plant some seed. Sell the result. Some will work, some won't. Adjust.
Which brings me to what to plant. Plant what You like to eat. If you sell it you'll make some money and if you don't sell it you can eat it, can and freeze the rest or feed it to the chickens...nothing lost.
I love garlic. I hate spending money. The garlic 'seed' companies charge $20 a pound or more for their seed stock. Walmart charges $3.89 a pound. I bought it from Walmart...some sort of hybrid white skin. Twenty bucks for 5 pounds. I planted the big cloves on a mild November day and forgot about it till late June of the following season when I harvested enough to go to market and make $100 one morning and eat all I liked. And guess what I have left for seed? Five pounds.
Sure the hybrid reverted to it's dominant parent stock which was interesting. What had been big fat white bulbs with 3 or 4 fat cloves and a bunch of little tiny cloves (useless!) now became small bulbs with 4 or 5 big fat cloves and NO tiny little cloves in the center. No waste! So that's how I sold it to the customers. They loved it because everybody buys big fat bulbs with tons of tiny little cloves that they hate! Now I'm the 'go to' garlic guy!
Save your seed...mostly you'll get SOMETHING. Select the ones that do best and you have a unique product. I don't buy super exotic hybrids but mostly heirloom and some F1 crosses (first generation hybrids) that I select out. Personally I don't worry about 'organic seed'. The crop will be organic cause that's how I grow it and that's all that really matters. And may Monsanto et al rot in hell for their genetic monstrosities.
Finally, as Wally has stressed for years, it's about square footage (and time and labor) for the dollar. I learned that lesson my first year at the farmer's market from my friend Lloyd Allen, long before I found SPIN-Farming. I wondered why nobody was selling sweet corn and I overheard Lloyd say to someone, "Why should I spend a whole season growing sweet corn to make a dollar off that 3 sq. ft. once when I can plant 3 sq ft and make $3 per month for the season with radishes? And do it on a stool?" My kinda guy, Lloyd was!
Finally the best piece of advice I think I ever got was, "When you're up to your ass in alligators it's easy to forget that your original intention was to drain the swamp." Put more plainly, don't get 'lost in the weeds'. Plant seeds, sell food, make friends and help your neighbors. You'll learn as you go.
To sum up, the single most important thing you can do is get a soil test, then get some kind of seed in the ground as soon as possible. When you get a harvest take it to market. We humans have been doing it for 10,000 years at least. It's in your genes. Like a spider and it's web. It's a really good thing. For everybody. You're going to do great.