Knobster nailed it.

The one thing I'll emphasize is that depending on just how they start things the beginning may be a total zoo. So show up alert, it gets easier to stay safe once things spread out.

IF the ride is on closed roads there is one very nice trick, ride on the 'wrong' side of the road. It is amazing how much we are creatures of habit and that side will be much less crowded. DO NOT use this trick is the road is open to cars!