I'd say hang on if you can. It's a slow starter, but around halfway (of the first book) it becomes incredible.

Also, there is no need to read it all in one go. Don't feel guilty for dropping it, reading something else and picking it up again. Years later maybe. That's fine.

I found that I enjoyed the first books more than the last when I was younger. I am nearing 60 now, have read them again, and the last book hit me so hard I could not breathe or think straight.

Haven't seen this mentioned yet, so:
You can write care of the publishing company.

As others mentioned, nothing beats a handwritten letter. But you don't want to go into stalker mode to find the writer's address. Publishing companies will absolutely forward the authors' mails. They might open it first, to screen the weirdos. So, don't write anything horrible, avoid nudie pics (how is that even worth mentioning? anyways), be positive and your letter will reach the writer. Don't send anything else though, like an object, even if it means a lot to you that this writer should receive that object. Red flags.

And yes, speaking for me personally, it's always great to receive a nice message from a reader. Unless you're a superstar, writing is a lonely business.