Think of it this way: 100 miles is only three 10 mile rides and one 5 mile ride more. A 10 mile ride is a piece of cake. 5 miles is around the block.
Oh. And all that stuff they said about food, water, yada, yada yada.
Of course if you are doing the Hardscrabble Century in Coloado a lot of the hard stuff happens at 80 miles which is not a good place to have hard stuff happen.
Stuart Black