Good advice on staying away from the front of the pack. Do you have any opportunity to practice riding in a group?

How many riders will there be?

I rode El Tour de Tucson last year for the first time- over 5000 riders were on the long route. I started in the middle and a lot of folks passed me. It was not that long until a lot of folks were spread out and it was never a big unwieldy group after the first section.