Biking cross country jitters

I 'm sitting in a library in St. Petersburg, FL anticipating the adventure awaiting me in the near future. Departure date is June 17th, 2010. Finally we have that writtin in soft stone. I'm ready to hit the road but also very scared of the unknown. I worry about money and what we will eat, where we will sleep. How the hell I'm going to bike everyday for 40 to 70 miles a day when just last year this time I was knocking on 200lbs door and trully unfit. I'm confident that in the end I wont no why I was stressing so much but currently I wonder if there is advice out there that will sooth these feelings / thoughts I can't sseem to shake.