Most people on this forum don't let their kitties outdoors, which is probably why no one has responded yet.
I do let my cats outside, because I live in a VERY safe place for cats... my other cat lived a nice long life and he was allowed outdoors... he died of heart failure, which had nothing to do with his going outside.
So anyway, it seems like you, too, live in a safe environment for letting your kitties outside. A few tips for getting them accostomed to the area: put their used litter in the yard for the first few weeks. This way, if they were to get lost, though that's very unlikely, they could find their way home by smell. So I think that you should have no problem letting CJ outside as long as you do that. Also, when you open the door and call her, and she comes, give her a nice treat so that she knows that coming inside is the right thing to do. If not, don't worry, as soon as it gets dark or she gets hungry she'll come back.