Don't know how old you are, Wasp, but if you can do 75 miles you can do 100. Just take it easy the first 50 miles so you still have some ooomph for the end. Chuckanut for those who are asking IS hilly, but most of the hills are not cruel hills (one is).

oh, the age reference. If you're under 30, you can do ANYTHING and get away with it. If you are older, you will pay mightily for riding without
the appropriate training.
good luck