I just finished a big local ride here in Michigan called the Blue Water Ramble. I have never done anything like this -- an organized ride event OR the distance -- but it was a very enjoyable experience. Of course, the absolutely perfect weather was a big part of that: cool, sunny (after early fog), and no wind. Also a very flat route helped.
This ride goes along both sides of the St. Clair River, which is the channel that Lake Huron empties into, and which flows on down towards Detroit and Lake Erie. They had routes of 40, 60, 80 & 100 miles. Since this was new to me and I ride a fat-tired bike, I chose the 40-miler, but am sure that I could have gone 60 today. The really cool part is the "international" aspect, as you take a small-town ferry across to Canada, ride along the Canadian side for a while, then another ferry back to the U.S.
They had plenty of food at the rest stops, not to mention the possibility of really chowing down at the lunch stop, which was in a beautiful riverside park on the Canadian shore. There are up to 1500 riders in the event, but there's about a 4-hour window when people can register and start out, so it was never crowded along the roads or at any of the stops. And all this for only $15!
I'll definitely be back next year, maybe to try for 60, but this year's experience would be hard to top.