Time travel is fraught with terrors, personal time travel most of all. Whether it is in the discovery that one's ancestors were criminals and murderers, or only that one's youthful tastes weren't as sophisticated as one thought (see note #74, on The Secret Garden here, for one example of that phenomenon).
My own childhood favourites include a surprising number of Brit-lit classics. Lewis Carroll and A.A. Milne, of course, held pride of place, along with the likes of Kipling's Jungle Books, Lang's Yellow Fairy Book, Edward Lear's nonsense poetry, Graham's Wind In the Willows, Barry's Peter Pan, Edward Ardizzone's marvellous Little Tim books and the Lonsdale/Turner translations of Tintin (just off the top of my head).
And E. Nesbit's now-105 year-old classic, The Railway Children, which I recently pulled from my shelf, starting another voyage into my own deep past.http://ed-rex.dreamwidth.org/15318.html. Comment there using OpenID, or here as per normal.