This thread just has biiiiig neon signs that say "KOKORO BAIT"
Anyways - snowangel kami has Tactics about right. It's very clean, with very little cursing and nudity, etc. The one problem that you may have with it is that most of the characters in the plot are based off of traditional Japanese youkai/oni and since Kantarou studies Japanese foklore, he references Shintoism and Buhddism quite a few times and admits to having built a small shrine to Haruka when he was a child. In the ADV translation, they call Haruka "demon-eating goblin." This is a somewhat shaky translation, since "demon" is translated from "oni" and would be considered more of a troll-like creature or a spirit. Much in the same way "goblin" is translated from tengu (Haruka is specifically a karasu tengu). Neither "demon" nor "goblin" carries any of the same meaning it does here in the West.
a few spoiler-esque points to cover:
[spoiler=volume 2]In volume 2 Kantarou is working as an interpreter in a Catholic church and seemingly gets beaten up by a reverend there. Sugino makes a couple remarks like "what kind of religion is this!?" but they stem from the fact that 1) the reverend is actually a corrupt priest in the church and a Satanist and 2) Sugino really doesn't know much about Christianity to begin with, so I think his judgements are based on the circumstances and are no way a jab at Christianity.[/spoiler]
[spoiler=volume 3]In volume 3 Haruka and Kantarou are in a village assissting a diviner and her daughters with a special good-luck ceremony. The diviner's daughters both develop affections for Haruka and Kantarou. One of the girls tries to kiss Kantarou, and the other sort of slides her kimono down on her shoulders a bit in front of Haruka and tells him she likes him (nothing is shown but her shoulders). This scene is short lived and both Haruka and Kantarou basically go "whoa, I'm too old for you!" and that's the end of that.[/spoiler]
I'd go over books 4-6, too, but who knows how long it'll be until those are out in the US, so I'll wait.