When I hiked the PCT in 04 I had not quit my job - I had been fired. I had already been offered a new and even better paying job, but I turned it down in order to hike the PCT.
I can only agree with everything everybody else has already said, meaning more or less: Go and hike and worry afterwards.
But I want to add another important thing about finding a new job:
When I came back I was looking for a new job and I got the first one I applied for. The new one is a big step up from the old one.
When I came back to Germany I was so completely relaxed after the PCT that I didn’t worry at all about jobs. My plan was to look for a new position for about 4 months. If something interesting comes up, I would take it - if nobody is interested I would just go and do another thruhike.
I think it was this extremely relaxed attitude that gave me my new job at once.
Another interesting experience was the following: I was wondering how people in the corporate world would react to my thruhike. Would they think I am completely nuts? On the contrary: My new work environment was very curious and admiring about my thruhike. Even the headhunters were completely impressed and interpreted the thruhike as something positive (persistence, endurance, challenge etc.)
To summarize it: Go take a hike!
German Tourist