As nostrademons said, I'm expecting junk code. But that's fine, because junk code still conveys the idea of what you're trying to create far better than the English language ever will. There's a reason why the YC application form asks for demos.
Pitch them your idea. That's going to be the challenging part. Find the one great coder who gets excited
Better to have two or more excited coders so that you can pick the best one; and your odds of having multiple coders excited by your startup are vastly higher if there's actually something for them to look at.
The only problem is, well, being able to pick the best one. From what I'm gathering, the OP is the not-software business type, and as such, he really doesn't have much of a metric to use to determine whether or not the person he decides on dragging into the whole mess as a co-founder will be up to snuff.
Worse yet, he's in an unfamiliar town, and as such, the trust metric he'll be using for people that he meets in SF is probably going to be out to lunch for a while until he can get his bearings down. This is the most troublesome part for the simple fact that it doesn't matter how much networking you do if you can't willingly place enough trust in the people you meet.
For now, to the OP, do everything: Network with people, kludge a project together, and do business development. Welcome to the club.
Pitch them your idea. That's going to be the challenging part. Find the one great coder who gets excited
Better to have two or more excited coders so that you can pick the best one; and your odds of having multiple coders excited by your startup are vastly higher if there's actually something for them to look at.