In the main holding area there are plenty of places to sit...it's on Delancey Street outside of Finnegan's. The restaurant is open if you wanted to get something to eat or drink but it's always wall to wall people so I would avoid that if at all possible. If you get there right at 5pm when the holding area opens, you can grab a nice step to sit on but if you wait you will have to stand or sit on the sidewalk curb...which isn't that bad. Lots of people just mill around and people watch. There are some interesting folk every year.
Finnegian's will be packed, so try to get to the area around 4:45. That should give you adequate time to be seated and eat. The food is really good there!