Do your homework on what trails you would like to go on. The point of the trip is to enjoy yourself. You don't have to try to keep up with anyone or think you have to be a hero if you don't want to do anything. The whole group won't be on one trail. There will be a lot of people and they will break up and go on trails they want to go on and feel comfortable on. Join in with a group that is going on a trail you feel comfortable on. Or pick a trail yourself and ask who wants to join you, you'll have takers that will join you. Have fun and enjoy, it's a great place, trails for all level of skills.
I did Porcupine Rim. Every time I looked out of my driver’s side window, I thought I was going to poop myself.
My tires were always a foot away from what looked to be a one mile drop straight down.