Matt really nailed it as far as my experience goes (both posts are fully accurate, though). I ramp-launch from a sand ramp in the OBX and before I back onto the ramp I step the mast, start the main, usually hoist the jib, etc. There's a muddy area next to the ramp where I will move the boat to while I park the car, but if there are other boats waiting for the ramp I will try to move the boat a bit farther away (there's a sunken boat next to the ramp so I can use that as a dock). When the car is parked all I have to do is spin the boat into the wind, hoist the main and start to maneuver. It's an emergency ferry landing and crab dock, so there is junk everywhere. I do everything I can possibly do before backing onto the ramp. Make sure to pull out plenty of mainsheet so that you aren't sheeted in as the main goes up.
And look for overhead lines first! I've seen ramps where you almost have to rig on the ramp due to overhead lines. It sucks to rig the boat and then notice that you can't get there from here.
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'00 H16 #104691
'78 H16 #32692 ex-rental [gone]
Old Holsclaw trailer
My Hobie 16 pages