Region: Middle Earth
I enjoyed the read, as well. It's always informative to hear how others might sum up something.
Personally, I always thought of Valinor as having been moved more to a separate dimension/otherworld, though I don't recall what the actual text says. I really like the idea of envisioning it more as off-planet. Pretty cool.
In one of Tom Shippey's books on Tolkien, he talks about his own interpretation of the departure to the west undertaken by the hobbits at the end of the book. Keeping in mind Tolkien's own disdain for allegory and insistence that such devices are impractical for analyzing his works, Shippey discusses Tolkien's own experiences in the first world war, his and other returning vets' experiences in attempting to rejoin the civilized world, and how many of them felt such a re-acclimation to be impossible and had to "leave" once again. It doesn't have to be a one-to-one allegory, but the emotions and experience certainly seem to have contributed, in some way, to depicting how and why story shows the ring-bearers departing after all is said and done.