I think what I was getting at, is that The Hobbit and the beginning of LotR seem transitional in style. There is gradual shift in tone from humour and innocence to drama and maturity. The very end of The Hobbit, with the Battle of 5 Armies are a foreboding of things to come (though Tolkien himself wasn't even aware of it at the time he wrote it).
Fellowship, indeed continues with the humour and the innocence that pervades The Hobbit. But it is more mature and even less directed towards children. As the story moves along, Middle Earth gradually takes shape, and before we know it the Drama shifts into High Romance (in the old sense of the word as applied to Beowulf and the Arthurian Legends).
And funnily enough Roverandom fits right into this discussion. Eldorion and I were discussing this very thing on another thread. Tolkien wrote Roverandom very much in the traditional style of a "children's" book. But felt a little guilty about "writing down" to his children.
Eldorion found quotes from Tolkien's letters that indicate Tolkien wrote the Hobbit as still directed at children. Yet I think, based on his feelings about "Fairy Stories" (as noted in his essay On Fairy Stories, he took umbrage at the notion that they should be considered as "childish"), that he was already shifting gears in The Hobbit. Hence we find a work in transition, that has some elements of a "children's" story still in place, yet as he wrote it, it expanded into a Grand Epic. And this process continued into LotR.
As the Hobbits ultimately represent Tolkien's vision of an ideal pastoral country life-style with all the jolly comforts of hearth and home, it is no wonder that these are the parts of the books that make us feel so cozy. They are my favourite bits too. The ending of LotR is bitter-sweet. The Elves and Magic are leaving Middle Earth along with Frodo and Gandalf. Bit sad really