Better late than never.
I know this is a bit late so far as this thread is concerned, but on Wednesday, I finally got around to measuring the widths of the paths, and this is what I found:
Southbound (Newer): 48" minimum at auto gate, 60" typical at posts
Northbound (Older): 40" minimum at gate, 44" typical to railing
Mind you, that 40" is on the ground, making it the widest your trailer or trike could be. Above that point, however, there are a few more inches of room.
It might just be the connectivity and not having to cross through that tunnel, or possibly the fewer pedestrians, but I would still say that I prefer the older, narrow path for riding. I still advocate to just travel with the traffic on the bridge. It makes it less hazardous to others that way. While not signed, this tends to be the de facto rule. I would even dare to say that the relative number of cyclists going the wrong way in this case would be similar to that of the signed Hawthorne bridge.
Gas Tax Holiday? I must be on gas tax retirement.