We've been going to the Wheatland Music Festival (variety of Americana music) in central Michigan, Remus, MI, for 16 or 17 years now. We've always taken our RV during that time. It's also a 3-day event the first weekend after Labor Day. We've also gone to a few bluegrass festivals of the 2 or 3 day variety.
Generally these festivals do not have electric or water, much less sewer hookups. At Wheatland they do not want generators operating either. I volunteer at this festival and haven't had to enforce the generator rule though. They usually do not allow campfires, although you can grill. They often have food vendors at these events if you don't want to spend time preparing food and cleaning up.
Other festival goers sometimes decorate their site with flags or things related to type of music played at the festival. Getting a good seat at the main stage can be a priority for many and sometimes set up their lawnchairs before setting up their campsite. Expect a fair amount of drinking, but festival organizers generally make sure it's toned down or they may have some form of security there to keep the event pleasureable for everyone.
Knowing when to get there and where to place your camper can be an important issue. One reason I began volunteering for the job I do is because we get in the night before the event and have the ability to pick out our campsite. Otherwise there is usually a long line of festival goers that have been going for years and know when to get there and where to set up camp. The line can take hours and getting there late can mean you get what's left over campsite-wise.
Generally RV's are placed in an area where there are other RV's, but often tent campers are in the same area with a variety of set-ups, some well thought out while others are as basic as it gets. Sometimes people will play music are their campsite with instruments of their own or CD's on a battery operated box. If you're concerned about going to bed early you might have a bit of noise in your area. It may be fun and entertaining or it could be less so.
I'd say keep an open mind. Relax and have fun because that's what other festival goers have in mind. Try to find out from either the organizers or someone else that may have gone before what to expect. Organizers want their guests to have a pleasant experience.
Have Fun!!!
PS: I just noticed that you have a "premium" RV pass. This is likely a positive thing. You may have a great camping area, possibly with electric, which can come in handy on a hot weekend. You may enjoy your experience so much that you'll go for years to come. That's what happened to us.
