What are the different routes to infiltrate Liberty Island?

I am playing through Deus Ex's first mission, where the NSF have taken control of Liberty Island. My mission is to infiltrate my way in and make my way through the statue to find the NSF individual who is coordinating the assault.

I went in through the front door, which involved dealing with a variety of security bots, gun turrets and well armed guards. There was a fire-fight and many people were killed.

I would like to replay this mission but without resorting to wiping out a small village worth of people. What are all of the different routes you can take to infiltrate the statue of Liberty?

Mainly your options are going through the front door and using the Tower of Babel on the back corner. Now there's 2 or 3 ways you can approach going through the front door (getting the key from Filben, using the security code conveniently found outside the path of the NSF bot, or just plain blowing it up).

That security code lets you disable any of the turret guns and cameras you find on that lower level as well, so you might consider using that as well as thinking about how you approach something. The most direct path is often the least stealthy path. But as far as things go, you can complete Liberty Island very easily by ghosting. It just takes a little practice.