Doug, there's a proven method of moving stones laterally that doesn't involve dragging. Using that, placing the lintels over the tenons would seem to be feasible.
It was devised by Gordon Pipes, who's well known here. So far as anyone can tell he's not an alien. ;)

His website explains it...
www.stonehengineers.co.uk

or, if you've got a few hours you can read how all his ideas were discussed in huge detail on this forum...
http://www.themodernantiquarian.com/forum/?message=123773&thread=12607