you can still ride through the port, though it is technically verbotten. when i lived in the neighbourhood we'd ride along there all the time: got stopped once by security, but only because we were taking pictures; usually they ignore you. best not to blow the checkpoint but if you ride west along wall street, about 2/3 blocks before you hit hastings you'll see a little park on the right with a (n open) footbridge leading over the road, and stairs leading down. hump you're bike down and you can ride on the flat with virtually no traffic all the way to crab park
That footbridge is at the little park at the north end of Nanaimo St. Last time I looked, the port had installed a locked gate at the bottom.