I went to Open House York this weekend with tours at the memorial and 7WTC and got a few interesting bits of info. According to the marketing rep from Silverstein:
1) They anticipate streets being done in 2013 in time for 4WTC to open (1 WTC won't open until 2014)
2) If financing goes according to plan, towers 3 & 4 will be done in 2015, though she didn't give any hint as to whether there are any prospective tenants lining up
3) Podiums are definitely being built for both towers. They are being reviewed by architects to figure out how to cap the podiums if need be so that retail can be accessible (she made a comparison to PA bus terminal. Yikes.)
4) Tower 2 is not currently undergoing a redesign like tower 3 did.
5) The pyramid frame atop tower 2 is meant to be enclosed in glass even though it doesn't look it in the renderings. (I asked because the floor to ceiling model had the tip clad in plexi)
Now as a disclaimer, these things aren't out of the mouth of Larry, but since it was a marketing rep, I would trust that this is the info they're telling prospective tenants.