the one thing for certain here is 100 miles on a bike is MUCH easier when you have no way to measure it.
Come on out and bring any computer you have , that will last 8-10 hours.
Everything I've tried is dead long before I get half-way.
It's a "LOOP" "Closed Course" practically.
I can count and do math.
A LOT of people ride it. IT'S been measured by every computer out there.
Edit/ You're right about not having something in front of me while I ride, telling me how far I have left to go, making it "easier".
I'm laughing, smiling, waving, and honking my goofy horn at the folks out enjoying the day at the beach.
We're all outside at the Beach; happiest place on Earth.
It is the easiest 100 mile bike ride there is.
120 miles in a day is my record, and it was my best Christmas ever; Oct. 8 2019
Like Pete
@SKPC said, any rider can do it.
Come ride with me, it may be the most fun you've ever had on your bike.