My first priority would be to save myself so I would just self rescue, as tying lines to a cray float sounds a bit risky (we are kiting at a surfbreak here, so there is wind, swell, current, ropes and lines to contend with) and as Reflex said the float would likely get pulled under anyway.
Once I had rolled up the lines and reached the kite I wouldn't consider there to be much risk associated with trying the Kitehard method of self rescuing out to the board, so would probably give that a crack.
If the current is taking the board upwind and it's only got three little fins in the water (or from memory one funny looking one, in Waveslaves case

) I would just make sure I was hanging in the water myself as opposed to lying on the LE and surely the current would assist me in going upwind aswell.
If I get to the board (and as all the endings to this senario are going to be fictitional anyway I am going to say
I do (didn't think I would ever say that again

)), well and good if not I'd just turn and head for shore, it was only a board anyway.