bear in mind that if you can ride 75 miles you can always manage 100- just envisionn it as one of your local rides. For me the last 25 miles is the equivalent of an easy ride to a local coffee shop I sometimes do on Sundays.

Also bear in mind that even though you may be theoretically starting at the front of the pack, to avoid any problems, you havee to be able to ride fast enough to stay ahead of the pack including hammerr heads and show offs.

good luck !

marni