Rock CF is a great event. It takes place at the end of March which can be a nice warm up for spring marathons, which exactly what I used it for. The course winds around the perimeter of the island which makes it pretty scenic along the water. It is also pretty much completely flat. There was less than a handful of gentle inclines, but nothing really worth mentioning. Late march is not the most beautiful time in Michigan as things aren't really budding yet, but the water adds a cool element. The down side to that is that if it's a windy coolish day, you're going to feel that wind coming off the water, so dress warmer than you expect, you can always throw things off.
There isn't ton of crowd support, as it's a smaller race, but for being a smaller residential island, I was impressed with the amount of people who do come out. At one point in the race you get to run through an airport hanger, which I have heard typically has a bunch of people in it to cheer you on, however that wasn't the case this year. But being towards the end of the race, I could see how that would be a good boost to the finish.
Parking is pretty easy. You can park at the middle school and walk over easily enough. If you arrive a little later there are free shuttles over to the airport where there's lots more parking, but I would try the school first. Check in is inside the school gym which is a great place to keep warm before the race begins as, the start line is just outside.
After the race, the gym is filled with bagels and the famous Rock CF cookies that help after a race. There was even a massage station which I always take advantage of. It's free to get a quick massage and it really helped.
For those interested in shirts and medals, Rock CF have some pretty sweet ones. Probably the coolest shirt that I've ever received at a race and the medal was a heavy guitar pic which was really sweet. If you live in the Detroit area, or just across the border in Canada, I highly recommend this race that goes to a great cause.