You guys probably have seen me do this at Squampton and The Gorge:

Stick rolled up sail through one harness line.
Shove two piece mast through same harness line.
Lash sail and mast to the clew-end of the booms with the outhaul.
Thus carry the sail/mast/booms with one hand.

Stick extension onto the mast track of the leopard skin board.
Carry the leopard skin board under your other arm, with the deck of the leopard skin board facing out, and fin forward. Use your hand to grip the bottom-most front strap.

Wrap your waist harness around your waist (duh!). Stick can of energy drink in your pocket. Walk to water's edge and rig. Sail.

"Happiness is a hand-held sail" - Wayler Windsurfing circa 1980