Best bivi sites for a two day trip are about two pitches up the NE Ridge. You can make it in 6-9 hours depending on how fast and light you go. The rock up to these sites is totally scrambleable (actually the first 2/3 of the entire ridge are, even for me). About 1 hour further up is another great location.
Get water at the slabs as you cross the glacier because the route is obviously dry. Oh yeah, bring crampons because there is one steep section of hard snow with bad runout.
B.T.W. don't follow the snow finger up to the left at the base of the route. Go past that and cross over the red rocks, then turn left to follow the gully up. You'll know when you are on route because gully is well traveled.