Not stupid. Reasonable and appropriate for the times.
The way I see it, the set up needs to be a long term partnership. You need a farmer, the farmer needs a farm.
If the system crumbles and you relocate, it would be a while before you would have the skills to operate the place without your farmer. You will also want to share in the benefits of relationships your farmer has formed with the locals during your absence.
If the housing were in place for 2 families, this could work out well. One home for the farmer and his family, the other would be for you and your family. For the length of the commitment needed, it would be prudent to consider more than unmarried farmers. Perhaps you could rent out one of these homes to help with the money aspect of the enterprise.
I was involved in a situation not unlike what you are describing. While it was initially 'not about the money', it became 'about the money' real fast. The plan went from 'develop an organic farm' to 'start an orchard' to 'can you start a salsa garden' to 'can you build some rooms in this barn' to me packing my bags. Prudence demands a full understanding of what you pay for, what Farmer pays for, what is done with income generated, what is available for an operating budget, and spell out accountability practices. Most importantly, what exactly do you want?
Next, while I like the concept, there needs to be a plan spelling out exactly what you want done with the property. "Develop a sustainable permaculture type farm" just isn't good enough. Is the place to have fruit trees, a
pond, berries, hugelkulture beds, double dug raised beds, how much area? What about livestock? Is
fence in place, who pays for the feed, is Farmer eating the livestock? Are the demands realistic for the nature of the ralationship-by that, does Farmer work a full time job to cover his utility bills or is he a hired employee with a weekly salary plus housing? Developing a sustainable permaculture type farm takes a fantastic amount of work. Does Farmer put in 40 hours/week on the place? What is the value of rent compared to a part time hourly wage? How much can be accomplished working part time? Is Farmer charged with construction of off grid systems and buildings or does he only focus on food production?
Is Farmer's primary objective to develop a farm or to develop a survival doomstead? You need to be honest with yourself and clear in your decision at this early stage because if its a doomstead you want, time is of the essence. In the event TSHTF, and you move your family to the farm, you would want off grid systems, hardy livestock, diverse crops with open pollenated seed, and properly stored food in place. For this, Farmer would need to be aware of current events and possess a wide range of skills.
If the farm is the priority, Farmer would need more experience with marketing the products grown and handling the paperwork. Your agreement would be oriented with a long term profitability motive in mind. Wether or not it's about the money is moot. It will be about the money. Setting up such an enterprise from scratch aint cheap. My estimate comes in at around $250k for those things I would want in place.
The farm plan has a
tractor, a truck, and an applicant with a clean driver's license. He gathers business
cards. Stuff is grown and sold to offset payroll, insurance and production expenses. The incentive to perform is cash driven. Farmer is a disposable commodity, same with the land. You'll want to be near a good market.
The doomstead plan has a team of draft horses, with a gene pool available locally, and a horse whisperer. He gathers canning jars. Stuff is grown, some sold, some saved for seed, some put into long term storage and kept rotated. The incentive to perform comes from within. Farmer is indispensable, same with the land. You'll want to be near a small town in an area of independent people with good natural resources.