I've done the ride a few times. There's one big steep hill that will make you happy to have a triple. A few other stingers as well. You're generally always around people, and it's obviously the most crowded right off the ferry as the event goes for a number of hours. Some people even do a "Chilly Century" and ride the loop three times. When I wasn't bonking because I had no idea about fueling over the course of 33 involved miles, I was having fun. The noisy and obnoxious people are always the ones to avoid, weaving in and out and in general being stupid (and dangerous). You'll have to bike defensively and take the downhill sweeping sections easy, especially in the rain, but it's not horrible.
It's fun to see a ferry full of a billion bikes. I'm a big car guy, and seeing and being among all the cars on a big ferry on any deck, feeling the wind, makes me happy. Seeing all the bikes (and all the people NOT stealing the bikes) and spotting the C&V or peculiar ones is a fun way to start off the year in cycling. You can buy chili and cornbread at the finish line if you like--it goes to a good cause, and chili and cornbread taste really good after a long cold wet ride.
