Of the people who have indicated they are going on Saturday, the consensus is an early start either from Rogers park or from the State park if you are just floating down river.
From the State park, the start time has been revised to around 9:00.
From Rogers park, the start time will be about 8:00....
This means the groups will rendezvous on the river somewhere downstream from the State park. There are multiple places to stop along the river and the idea of starting early is to allow more time on the water and at various stops. If you are planning on going and considering a different time, you might want to comment on your time to help allow for gathering with the group.
If you want to discuss, send me a message on Facebook.