To get off the grid and maintain your current lifestyle you need to create self sustaining systems for three basic things: water, power and electricity.
For water, having a number of sources if recommended. Using groundwater from a spring, creek or well is one source. And capturing rainwater from runoff from your roof is another source. These combined can provide most of your household needs.
A spring is ideal, but depending where you are they can go dry in summer. The same goes for a well. A well is obviously more expensive. You have to get a dowser to find the sources of water, then you have to dig the well, and depending on whether your run into bedrock, you may need heavy equipment to drill through it. Both of which costs money (in the range of 1000 - $6,000 dollars depending on depth).
Rainwater run off is great, because the water tends to be more pure than ground water. And you are not as susceptible to ground water pollution from neighbouring industry. However, rainwater must also be purified due to contamination from bird droppings on your roof. This is usually manage by having two storage tanks. One smaller one fills with the initial rain which will capture the dirty poopy water. Once it is full you have a mechanism to switch the flow to your main cistern.
The other thing you have to deal with is ensuring the water is oxygenated (which can help to kill bacteria as well) and also making sure it does not get contanimated during storage. Oxygenation is done by flowing the water down swirly ceramic slides. Not sure how to keep the contamination from happening, but the mayans could figure it out so it is definitely possible.
Regarding power, there are many sources you can use: mini-hydro power, wind power, solar power seem to be the main ones for generating electricity. Mini hydro is the best because it tends to be constant, wind is the next best because it is cheaper and solar is the third best. All of these sources require investments in turbines, panels, solar cells, batteries, control panels, inverters, cabling etc. A wind installation might cost $1200, a solar $6000 and I am not sure about mini-hydro.
These systems also need to be maintained, so some basic technical skills are necessary. Cleaning, unclogging, oiling etc are required.
All in all, the greentech solutions are thought of as transition strategies that will be around for 35 - 50 years during energy descent, and the next generation will have to learn to use biological systems after this. ie horses, oxen, human labor, mecahanical windmills, mechanical hydro.
The other thing of course is that the appliances themselves that you run with your electricity: dishwashers, coffee makers, tvs, computers, light etc. Will of course break down as well. The life cycle for many of these products are now much shorter as well due to the manufactured obsolescence built in by our business "leaders". Something to think about as well.
Perhaps the market for mechanical devices will experience resurgence and growth: human power sewing machines, candles, kerosene lamps, hand coffee grinders, mechanical laundry machines. Do we have enough resources (iron, steel etc.) for a rebuild and rollout of these machines? How long will it take to relearn the skills needed for local manufacture? Other questions to ponder.
Given that there will be so much surplus labor available. Perhaps we will skip over these options and go back to a form or serfdom, as in feudal times, when people were attached to the land and their fates dictated by vassals and barons who own and manage the land.