I would definitely drive through the campground and look at the sites before selecting one if you plan on hanging. Yes there are many trees up there but not always suitable ones in the designated campsite where you will be staying. The hike in/cart in sites generally have better trees than the RV sites do.
Another option is to go the the DNR reservation site, select the park you want to stay at and you can view a picture of many of individual campsites by clicking on them.
MN State Park Reservations