+1 on both Mother Earth News and Dick Proenneke's documentary.
We've been out at our cabin for just about two years now and I wouldn't trade it for anything. We are spoiled though and are by no means off the grid. We have electricity, running water, an indoor bathroom, and even an internet connection. I'm particularly happy about not having to run out to the outhouse at -35C to take a poop in the morning!
My biggest advice to you would be to make sure you are realistic about your expectations and understand that there will be trade-off's you'll have to accept if you live off-the-grid. Living out at the cabin means both my spouse and I have a constant list of chores that keep us pretty busy - felling trees and bucking and splitting the wood for fire, garden maintenance, pumping water, etc. No longer can we just up and leave for a week or two without some serious preparation and a reliable and competent house sitter. Add a few chickens and a goat to the mix and hiking trips and extended vacations are suddenly pretty tricky to plan and execute.
Of course, for us it's a trade-off we happily accept to be able to live with such an intimate connection to nature. This picture was taken at midnight last week and was taken from our 'front yard'. Makes the hard work more than worth it.
In terms of the actual planning, I'd put together a list of things I'd want in a location (ie: access to running water, south facing exposure for the garden, etc) first. Once location is determined you can work your way outwards, deciding on the type of home you need, and how to get electricty, heating, etc.
Good luck and enjoy the research. And don't let the naysayers dissuade you if it's what you want.