So on my first play through I came across Little Lamplight could not talk my way in. Mayor McCready would have nothing of it. instead to prove I was a nice advlt I went to Paradise Falls and shot the whole place up to rescue the kids taken by slavers.

This time however I had the Child at Heart perk. I told the mayor his face looked like my butt and after some childish butt jokes and antics he thought I was cool enough to let in. However now I don't seem to have access to the quest to rescue the kids from Paradise Falls. I have yet to discover PF on this play through. So should I go there and then see if he has the quest?

I have two saves. one where I acted like a child and got in, and one where I hadn't talked to him yet so I can fall back to that one if needed. I kinda like how everyone seems to find me a fun advlt due to my child at heart nature. But I want to rescue the kids as well.

Can the rescue be done by just going to Paradise Falls?

The Fallout Wiki has this to say: "It is possible to complete the mission and get the achievement by just storming Paradise Falls and rescuing the children. This can be done without getting the mission from Mayor MacCready."

So it sounds to me like you can just go to Paradise Falls and rescue the kids.

I believe one of the kids will ask you to save the other kids when approaching Paradise Falls.