1. Southern Exposure: This is the most important feature, since a proper exposure means that your house will be able to gain heat from the sun in the winter and you will be able to place solar panels. Basically there needs to be a potential building site and a potential garden site that has unobstructed sky facing to the south.Even in town or in the city an apartment that has windows facing south will receive more sun in the winter and might be able to heat itself much of the year.
The garden part is assuming you want to feed about 4+ people you will need about 1/4acre of land that is either already arable ( good soil that you can squeeze and will hang together if slightly moist). If the soil is rocky or clay you will have to be able to bring in a lot of compost and may need to build beds. Typically arable farmable soil is near a river or creek, or somewhere where soil has been deposited like a valley.
2. Water- Sometimes you can find property that has municipal water, and hook ups to municipal power or sewage. In that case you need to determine what it will take to get a utility station set up for construction and gardening.
If the land comes with water it needs to be in the form of a spring or well generally. In California for example you are not allowed to use “second class waterways” which basically means creeks and streams. Those belong to the whole state not you as a landowner.
You want to have a number that tells you how many gallons per minute are produced by a spring, and generally how many daily gallons are available through a well/pump system.
Bring a gallon jug of water when you go and look at the piece, as well as a watch with a second hand, basically use the jug to figure out for yourself if you have at least a gallon per minute.
DO NOT buy land that has “shared” water or water easement from someone elses parcel. This is essentially a dry parcel and there is too much difficulty.
3. Easements- easements are legal agreements to share infrastructure between neighbors. Usually they concern things like a road cutting through your piece, or power lines. If you have a creek on your property fish and game can walk that creek for example.
The really troublesome ones are best to be avoided : sharing water, sharing a poor quality driveway.
If you provide water for your neighbor you can be forced to become their utility company of sorts, if they steal it long enough. You are responsible for walking the perimeter of your property and making sure that no one is squatting, taking water, or improperly using your land to access other parcels.
Basically 1,000gal per day needs to be stored and distributed to cover a full garden and four+ people and animals living needs.
This is how you determine the perimeter of your property, and you should always have the real estate agent find them with you and document them together. Now you can also see the property lines online with GPS images and often this is all available through a county or city online entity.
You want to be certain that the building site is on the property you are buying. (I know this sounds basic but many of my neighbors in Southern Humboldt got fooled on this one). Often the corners include iron spikes and official markers from older mapmaking methods.
These are the basic things you want to think about when you are looking at land. If the piece is nice and flat and has sun all over it you can live and garden pretty nicely on as little as an acre. The more you have rough soil and hilly conditions the more land you will need in order to accomplish a house, garden, and utility shed.
Our last piece had a beautiful solar/hydro setup that husband put in, if there is interest I can bug him to get the water flow needs in order to do the hydro.
Feel free to ask any questions, not sure if I have really covered the topic in enough detail.