“Using the hundreds of tons of water making up the radiation shield for growing bio-engineered organisms can sustain a closed loop life support system with an endurance of several years.”

Yes, the moons and dwarf planets in the outer system made up mostly of ice can possibly have tunnels melted continuously and eventually hundreds of miles long to support a colony. It is more difficult with rocky bodies but nuclear excavation using bombs as in project plowshare may be the answer there.
Thanks for the comment Robert

Now we have post peak oil to contend with.. stuck on Earth.

I wouldn’t want space technology to go to waste if we already have it and wish to preserve an intelligent slice of the human species with it, so.. I think a change in civilisation is in order, one that thinks in terms of volume rather than surface area of a planet. Subterranean C.E.L.S.S.