It's a fine idea, I've considered it myself. If you can put it all together and make it work, it will be a major accomplishment.
However...
Jumping in head first will present a great many challenges and I fear some of them will be insurmountable obstacles if you attempt to take them all on simultaneously.
Consider approaching this
project from a bootstrapping point of view: how to get from seed to plate. Because there are a number of facets involved, each of which will need to operate smoothly in order that the end project, the restaurant, is also able to operate smoothly, I think it would be prudent to examine each aspect of operation and build towards the end project.
Farm: grow crops and raise livestock
Lots of folks will say this is a major undertaking all by itself. There is soil, soil amendments,
water, mulch, seed selection and saving, tending the crops, tools and equipment, planning the diversity and location of plants,
greenhouse operation if you want the advantages there, tending, and finally harvest. Livestock involves breed selection, maintaining the gene pool, feed, water, housing, and harvest. Customer can be attracted with Pick Your Own vegetables and flowers, events such as a
hay maze or pumpkin picking. All this can be done, it's done all the time. The next step is easy
enough...
Farm Stand: market the product right on the farm to the customer
Pick Your Own is all well and good, but there are plenty of people unwilling or unable to get out there with the bugs and heat. You do the picking, wash it, and open up a produce stand. With a farm stand, you don't have to limit yourself to what is produced on site, you can bring in items from other local producers. That guy has
honey, the lady down the street has maple syrup, a guy across town has garlic braids. Your product diversity expands, as does your opportunity...
Processing: use the goods available to expand the product line
At this point you get into health codes, kitchen licensing, inspections, and heightened sanitation issues. Using the fresh product in the farm stand, you have the ability to process it into other products: jams and jellies, applesauce, hot sauce, relish, spreads, herbal blends and teas, soups and stews, salsa and tomato sauce, ice cream, canned goods, cheese-your only limit is imagination. You'll need potable water, a solution to sewage, bathrooms and hand wash for employees and customers. Insurance would be an issue to seriously consider. Your little farm stand now has recipes. The next step is simple...
Deli: Hot and cold foods ready to eat.
You would need a regular staff to keep this going. Once prepared, the foods have a shelf life. Being open for business just a couple days a week means that prepared product will likely be lost if the place is not open daily. The soups that were in jars are now hot and served to customers in cups/lids. A salad bar can be put together. Hot and cold sandwiches. Entrees for take out. Tables or picnic tables added outside makes the leap to consumption on the premises. Now tweak it...
Bakery: baked goods
Add on bread, pies, pastry, cakes. A brick
oven would be a novelty, but the food coming out of it can be inspiring. You still have the farm, farm store, and deli working for you. This is an add on step. You may not be baking every day. Maybe just Friday for fresh bread and Pizza Night. Take orders for holidays and special events. If sales warrant it, bake bread a couple times a week or every day. The staff is already in place from the deli. The investment here is in the oven and gaining knowledge. You may be ready for the last leg...
Restaurant: Diners come in, meals are prepared to order and served at a table.
Limiting most of your ingredients to what is available locally, your menu would change with the seasons. Food costs are low if much of the product is grown in the back field. You've got a variety of goods produced seasonally and stored on shelves, giving you out of season ingredients. You can still have the deli, with some of the product diverted to the restaurant, and the staff helping with some of the meal prep/baking/slicing. You've got the freshest bread. You still have outdoor seating, and could probably function seasonally with just outdoor seating. Adding a server and some kitchen equipment gives you this opportunity. How far can you take it? Indoor seating, table cloths, stoneware plates (produced locally), silverware, glassware, dish machine with
solar heated
hot water, chargrill, deep fryers (save the oil for biodiesel). Hang local artwork on the walls.
By bootstrapping the project, at each step along the way you have a viable enterprise. Each step here uses the previous developments for support, without sacrificing or discontinuing the previous step. Once you are able to operate effectively at each level you can move on to the next with the addition of equipment, some construction, and labor. You can probably find a business enterprise in your area right now that closely resembles each level, albeit with commercially acquired ingredients. You have the advantage of already having most of the systems in place before you move on. Waste from each step goes back to the beginning:
compost, livestock feed, fuel. At each step there is an investment of time, money and faith. Risk is mitigated by not investing in a later stage until the current stage is developed and paid for. Your start up capital gets the land and the farm. Sweat equity builds it from there, without giving up your full time job. Work the farm until it pays the bills, keep it going with sales on weekends. Move to full time when you are ready. The need for debt, investors, credit are all reduced. This plan will take time, it's not an overnight success story by any means.
With hard work, perseverance and dedication to an ideal, you don't need as much luck.