YY - the play on words of first leaf/first page was another thing I smiled at. I thought it was from the park in the prequel - but Glaikit I like your idea of it being from the park where the Tardis was hiding during the Christmas episode.
DP had missed it on Sat so we watched it again last night. On re-watching, there were other things that puzzled me about the 101 places book:
- why did it start at age 9 - was that Clara's age when she first met the Doctor in the park? Did something happen then, that we haven't seen as yet or why did she expect to go travelling after that point? And who gave her the book?
- she had crossed out every year from age 9 - but two years are missing - 16 and 23 - what happened to those years? Is this a clue that Clara has in fact been taken by the Silence for periods of her life and as such is a trap in the same form as River (but I'd really hope not - rather not have what is effectively the same plot twice..)? Did she 'lose' those two years in some other way?
With the Amelia Pond book - were the two boys effectively supposed to be the Doctor and Rory? One was fair and one dark. Did Clara just happen upon that book in a secondhand bookstore or library, or did someone give it to her quite deliberately?
And so to the first theories: DP thinks Clara is a puzzle the future Doctor has set himself, to get him back into the universe, engaged and motivated to protect the weak.
I have a niggling thought that Clara has been placed in his life in some way, too, but not by the Doctor. Clara is so like River in many ways. Quite flirty, quite assertive with him. "Run you clever boy" has echoes of "You watch us run". The "And remember" sign off - is that an admonition to remember who he is, what his mission of sorts has become? Is it an admonition to remember to always travel with someone - again a clear message from Amy and River? If River has realised that it is near the end of her time with the Doctor, is it possible she used her experience of being a genetic experiment and her ability to time travel, to plant genetic dupes through time and give them the personality/possessions (eg books) to tie into the Doctor's life? In effect, is she a living, breathing "Hello Sweetie" message through time, but with the objective of making sure he is not alone when River can no longer travel with him?
Also - on the plane he told Clara he was 1000 years old - was that shorthand or how does that tie in with the various ages he claims in The Impossible Astronaut epsiodes?
And a final thing I noticed - Clara's necklace is like an RAF wings badge on a chain - is there a link there to a previous story in that? Captain Jack? Something River picked up during the war? Is she in fact the various daughters of Jack through time when he was going through a phase for girls?!