Riding a lot will get you used to hours at a time on the road, and if you have any half-way decent roads near you that will provide its own inspiration. Go down a little hill and start thinking about going down big mountains; find a mile of quiet road and try to imaging riding like that for miles on end.
Unless you're young, rich, and foolish, you'll have to plan ahead. Read some blogs or some of these discussions to figure out how much money it'll take you. Do you need to win a lottery, or can you live frugally and save enough? Figure out how you're going to take 3-6 months to go for a bike ride; save your leave if you've got a job and talk to your boss about being gone that long. Can you get extra time off without pay, or do you need to plan on job-hunting when you get back?
I really like Willy Weir's writing. Get his books and read a story every couple of days. Space them out so you have time to digest and incorporate his gentle lessons.