CHRISTOPHER: I haven’t been enough a part of Rory’s life. So I wanna be around more, to be a pal she can depend on. I mean I’m not crazy, I know there’s already a life going on here and God knows she doesn’t need anyone besides you but … if you give me a chance …
LORELAI: I’ve always had the door to Rory open for you.
Christopher is making a massive understatement that he hasn’t been enough a part in Rory’s life – he’s barely been in her life at all, and only on his own terms.
Although Christopher agrees that Lorelai has “always had the door open” open to him, previous and future events make us doubt how much of that is really true. Lorelai is intensely jealous of anyone else developing a close relationship with Rory, and has even tried to stop her getting to know her grandparents better.
When Christopher makes a real attempt to get closer to Rory in a future season, Lorelai does everything she can to block it. It would have been even easier when Rory was a baby or a small child, and lacked the ability to see what Lorelai was up to.