A fellow demonstrated raising a pretty big lintel single handedly using criss-cross timbers and levers a while back. Not sure where that is on the net but Aubrey Burl was a witness.

A lot of TMAers acting as the Stonehengineers did the same thing in Crick, Derbyshire with a big concrete block (bigger than this capstone I think) but not to a very great height.

It isn't the getting it up that's the problem it's the moving it sideways that breaches health and safety regs. Like you say, constructing an earthen mound seems like the best way to tackle it.