I just finished re-reading Insomnia today. I adore that it's set in Derry, I had completely forgotten that, and I think on my first read through I hadn't read the Dark Tower series so it was very interesting to read it with having read DT. I also think that maybe reading it later in life(!) gave me a bit more of an empathy with Ralph.
I think on my first read through I was younger and I hadn't met the love of my life, my now husband (my Lois!) and to me the novel is so much about love, loving and losing and grief that I can really appreciate it now, how deeply we fall for people and need them and losing them is so hard, even thinking about losing them is so hard.
Unfortunately I do suffer from insomnia now and again, now is one of those times. On a good night I get about three hours sleep, my husband looked over at me reading Insomnia and was like "and you wonder why you can't sleep!" but my insomnia has been with me for the last 30 years or so, so I can't blame it on this book.
I also love how heroic Ralph was, he was being pushed along a bit but he has just so much love, compassion, and strength it was a real pleasure rediscovering this great story.