Friend.

there are many good manuals on underground or earth sheltered housing available, also a few good ones on home-generated powerl rammed earth construction is simple and low buck, but also labor intensive; one of the easiest and strongest methods for underground construction is to build a geodesic dome; dig out the spot you are to build in, construct the shape of the shell with rebar and concrete wire, then cover it with a minimum of 2" of gunite or shotcrete inside and out; the dome shaped structure will support 20 times the weight that a conventionally poured re-inforced 8" slab will.

as for power, i suggest getting a copy of Earth, Wind, and Water from the Mother Earth news, if it is still available; a small running stream with a mere 10 foot of drop can be used via a simple Pelton wheel turbine and an old style 18 wheeler alternator to produce megawatts.

The alternator on your car or truck produces 12V a/c to run your vehicle's electrical system, and this voltage is achieved by reducing the voltage from the battery applied across the field coil to less than one volt by the use of the now commonly built in regulator; find an old style truck alternator that carried a seperate external regulator, hook 12V across the field coil, spin it at 2000 rpm, and the alternator pumps out 120VAC at the full rated capacity of the unit; i.e. a 100 amp unit off a truck will produce 12,000 watts of electricity.

Anything is possible to an open mind coupled to a determined strong will; however, I do suggest researching and studying a lot, for it is readily apparent that you are not well versed in any of these fields of construction.

seeker

Another thing no-one has even mentioned is that the contractors will be like 'Gee this guy is building a bomb shelter / bunker' and tell all their buddies etc. So word will get out on the location for running to WTSHTF.

This is a possible thing:
If you submit planning permission the ptb now have a location to add to their list of bunkers which will go on their list for being requisitioned.
In the UK this exact thing happened when a guy was having his built and a guy with a clip-board came along taking down notes. When asked he stated it's the property of the government should a national emergency be declared! :O