gain entrance

Well, when you get there Mayor McCrady should be there, and he won't let you in. He calls you a mungo and tells you to get lost. There are now three ways to get inside:

1. Pass a Speech Check with McCrady, telling him that you're "really really nice"
2. If you have the Child at Heart Perk, there will be a speech option open that will get you inside.
3. You will need to do the quest, "Rescue from Paradise". If you pick the ladder, go to Paradise Falls. To get inside, you either need to pick up the quest, "Strictly Business", have low enough Karma to be let in for free, or pay the guard 500 caps to get inside. If you pick the former, take the Mesmatron to the Minefield and Mez Arkansas, take all his crap from him, and then put the collar on him. Head back to Paradise Falls to get your reward. You don't HAVE to get the rest of the people, you'll get more money and an achievement if you do, but you only need one person to get into Paradise Falls.

Now, you need to rescue three kids. There are a few ways to do this.
First, you can just pay Eulogy Jones for the three. It's 2000 caps for all 3 (1200 with a speech check).
You can also bust them out. To do this, talk to the kids. They'll tell you to mess with the system by either using a high enough repair skill to repair a box, or a high enough Science skill (I think) to do something else. Then, distract Forty by killing him (Turns town hostile) doing a speech check, or convincing or paying Crimson to seduce him. You can also just take Forty's Key, open the box, kill everyone in the town, and then get the kids out of there.
If you chose the non violent path, one of the kids wants you to rescue her friend in "the box". He's too big to go the way the kids went, so you'll have to kill a path for him. Get the key from Forty, and open the box. Get him out, and when you go back to Little Lamplight, you'll be let inside.

NOTE: If you don't want to rescue the guy in the box, just pass a speech check with Penny, and she'll go without him.

Hope this helps.

You can save the kids who the slavers have locked up in paradise falls. Once they escape they head for little lamplight. Follow them and try to keep them alive.

The "town" is actually located inside the Lamplight Cavern, so head there and go in! It is not too far from the office building with the monster basement.