Of course, there's also a large boatload of dead bodies, and they did not die well, so it ain't all sunshine and roses.
SUMMER IN ORCUS - Of the classic "ordinary kid winds up having adventures in a magic world before returning home having learned lessons/grown up a fair bit" genre. Though this is the only one I can think of off-hand where the child goes alone, and not with a friend/acquaintance/siblings--in this case, there's just a small talking weasel. Though of course Summer picks up companions along the way, so she's not alone for very long. There's some nice mythic world-building, a boatload of talking anmals, and a whimsical weirdness familiar from gearworld or Digger (which I really need to buy a copy of). Her return to home is also rather more satisfactory than in many other stories in the genre, though I won't say more, as I know some peole care about spoilers.
THE CLOCKTAUR WARS - Just as Summer in Orcus deals a bit with a very complicated, uncomfortable mother/daughter relationship, this two-volume story, for all that it's a fun romp, deals with questions such as faith, loyalty, past and potential romantic relationships colliding, prejudices of various sorts, and besetting weaknesses. Of all ursulav's works I've read so far, this one most reiminds me of some of Terry Pratchett's Ankh-Morpork novels, as there's a fair bit of social commentary built into the story being told, but in a way that feels largely natural to the story being told--cultural clashes all over the place, even between people who are ostensibly from the same culture.
There are a lot of dead bodies in this one, but what can you expect when you have an assassin and paladin's paladin as two of the main characters?