The Letters let you see his responses to questions from fans first hand.
And judging by how many letters he answered, I'm inclined to say that he
enjoyed it.
Granted, there were a few instances of people wanting to name puppys, plants
and other things after his characters that peeved him.
"I was piqued by the 'christening' of that monstrous 'hydrofoil' Shadowfax -
without so much as a 'by your leave.'"
And his tongue in cheek humor is evident occaisionally, beginning respnonses
with "thank you for your very long and inquisitive letter."
But for the most part he seemed genuinely happy that people were so interested
in his works to write him and ask him lots of
questions.
"I don't suffer from insanity...I enjoy every minute of it!"