During the test event they were only allowing people to cross in certain areas (at least where there were barriers in place for most of the main London area). They had Marshals managing such points and spread out along the route.
Given that this is the Olympics and they want to make sure there are no hiccups, I can't imagine they will let anyone cycle along the route once the closure is in place.
I managed to get a ticket for the final track cycling session, so I was quite chuffed about that. Slightly annoying that I could only get the one ticket though, so will be going on my own.
Also got a ticket to go up the Orbit while I'm there.