The guys give good advice, I would add that if you have not taken a long run before(multible days) toughten your butt up with long day rides, each day on a long run becomes a little tougher,day after day will wear on you no matter what you ride. As an aside, I always take a water bottle and snacks, sunflower seeds, m&ms stuff like that if you are riding hard, it helps, at least it makes my trips a little better.