Congratulations on finishing. It sounds like you are pleased with what you've done, which is great. I love typewriters for the very same reasons you mentioned in #2. As for getting into the story and becoming immersed, that is quite an adventure. I have yet to participate in NaNo but I did manage to write one novel a little while back. After finally getting into the story I almost forgot that I was writing fiction because it became so real to me. It's pretty fun, huh?The New York Trilogy is great. As a side note, Paul Auster is one of the few novelists for whom I've read nearly everything he's written. I want to read everything else by him. (To date Don DeLillo is the only novelist for whom I've read everything he's published.)
I also got the "characters doing things I didn't expect" feeling from the three times I participated in Nanowrimo. It is unusually fulfilling to finish a draft of something, I agree. Personally I think that Nano gets a little silly, though, when people do it year after year and never revise the drafts they have. That's one of the reasons I stopped.
I first heard of NaNo back in collegel. Some friends I met through AOL who had gotten into Live Journal were talking about this new movement where you write everyday for a month and create your own novel. A group of them were doing it and we all loved writing. I did not participate for whatever reasons and now over a decade later, I cant imagine dedicating the time to such an endeavor. I wondered if the magic that you described would happen and im glad to read here that it did for you. Maybe one day for me.