What they all sed, it's not the hills as the headwinds. After lunch on the Cindy it's flat till Lemon Drop and headwinds can be bothersome. Last year was just insane. There is a short steep hill after the first rest stop that's more challenging than Lemon Drop but nothing you can't do.
The last Lunachix ride, the 40 miles takes in the most scenic parts of the Cindy and is one of my favorite routes 'round here.
Registered or not you should go.