Hah, Into the Wild was definitely one of the things that got me interested in backpacking. And yeah, it pretty much was just an overnight decision to do it. I took a year out in college and said "what the heck, I'll hike the Appalachian Trail". Hadn't ever been hiking before, spent about a year planning and saving up, and it was still a huge shock when I got out there. For the PCT I didn't really plan a whole lot, since I already had the gear and knew what I was doing - it was pretty spur of the moment. A good friend of mine passed away at christmas and I decided I didn't want to sit on my ass thinking about all the things I wished I was doing. It's not massively expensive either - you're living out of a tent 99% of the time. I won't lie, it wasn't all fun and games - most of the time I was hurting, tired, cold, hot, wet, thirsty etc. Especially for the last month I was ready to be done. You learn to look past that, and focus on the little things that make it so great: the warmth of the sun on your skin after a freezing night; the taste of cool water after a 20 mile dry stretch; the feeling of a hot shower after two weeks of grime. It really simplifies life, and puts all the bullshit that you think is important into perspective. If you've got even the slightest interest in hiking, I'd recommend spending a week on a remote trail sometime - it's pretty damn therapeutic!
As for the lighthouse thing... the long distance hiking community is pretty close knit. Everyone either gets given a nickname or chooses one for themselves. I got given the name Lighthouse because of my ultra bright headlamp - I did a fair bit of night hiking at the start of the AT. When you're out there, that's the name you go by from start to finish. It's weird to come home after half a year and start using your birth name again haha!
Anyway, thanks for the kind words dude! Glad you enjoyed it.