To be totally self sufficient would be challenging if you want to retain the ability to live a lifestyle similar to the USA standard. That would take a good deal more money and land.
I have a pretty serious life goal of getting off the grid. I grew up on a mini Idaho hobby ranch. It was just under 10 acres. My parents still have a large garden, there own beef, and have a few horses. With careful management they are able to raise about 5-8 cows and two horses AND put up enough hay to get through the winter. The property has great water rights and creek frontage. The primary heat in the house is wood. The surrounding national forest provides all the winter heating for under a $100 a year in fuel for the truck.
The downside is that we never really raised any kind of stable carbohydrate like wheat. there really isn't much room for that. They do have a sizable garden and orchard which offsets a lot of food cost. They do a bit of canning, but nothing extreme.
I think to be totally self sufficient you need to produce your own transportation also. While the horses would do just fine in an emergency....I would like to see a way to harvest your own fuel. I think that oil crops require a lot of land and time. I would love to build an algae based system using a greenhouse....
An easy option, but an expensive one would be a solar power system for electricity.
No matter how 'self sufficient' your property is its hard to get away from taxes and insurance for day to day living ( car insurance, health insurance, telephone, internet )
Best of luck...