I recently built my own house. I had the idea of "no electricity" in mind when I was designing. That idea has been great since the area has lost electric for 3-5 days a couple of times. One result is having lots of guest who would normally have never considered living without electricity. That's another story though. My first comment would be to keep things as simple as possible. Consider the fact that you may not stay there forever. My last house was going to be my last, DOH! I would get on-line and get lots of fabulous ideas, but then I would alter, change, contemplate, procrastinate, and never get anything resolved. Take care of the basics first.
My house and plan is no where close to perfect. Now that I'm living in it I have discovered many simple ideas that I could have done to prevent lots of extra labor and cost. At the same time, I am pleased with the results. List of considerations.
#1. Water source. I have a spring that runs all year round and puts out 10 gallons per minute. I was very lucky to have the location. It was an investment my grandfather made who always preached about not being reliant on machinery or expensive energy (electric, gas).
Drainage of water is just as important. I do not put any chemicals down drain except for soap and shampoo. I have no septic tank. I do have normal pvc drain system. Water goes out pipe to natural filtration system. There is lots of information about this on-line. I actually grow food due to moist soil. I have system that allows me to screen waste (basically poop and toilet paper) and remove to area that allows waste to dry out and be used as fertilizer for pasture. This may seem contrary to what your used to but it is actually better for property. Besides what happens when the truck that sucks out the tank no longer comes? Anyway, something to think about.
#2. location of house in regards to water source. Sewage. If no spring available be sure to design roof to maximize rainfall. I wouldn't want to rely on well. Very expensive. Local neighbors are having to drill deeper for wells. This is in the ozarks also! Amount of water from rain is overwhelming when measured. plus it's an old idea that has already been proven.
#3. In the future heating will be harder due to lack of or price of electricity or gas and even wood. Go cut down 4 ranks of wood by hand, saw and split and then carry distance to home with manpower. Harder than it sounds. Don't clear too many trees when building. Just ones that could blow on house.
#4. Lumber is actually more environmentaly friendly. More energy is used to create concrete and transport. My area has small mills that sell lumber for half the price of lumber yards. The boards aren't always as nice as you want, but look at the lumber at the lumber yard and see if much difference. Lumber has more flexibility. Trust me, you will regret too much permanance in the structure of your dwelling.
#5. Size. I am very pleased that I fought off the constant urge to want to add more space and gadget systems. What happens is budgets go higher and time becomes an issue. Don't get me wrong, I set my house up to be added on very simply if need be.
I could go on and on but this is just some considerations.
Good luck.