I go every year to MerleFest in late April - a four day "Americana" music festival in western North Carolina. There are crowds, but $230 for a reserved seat at 4 days of music avoids the worst of the crowding.

The National Storytelling Festival every October in Tennessee is modestly crowded but still very enjoyable.

I've given up on New Orleans Heritage and Jazz Festival - always a great line up but very crowded and intolerably hot.

Mud and camping out? No, I do not go anywhere that does not have a real bed and flush toilets!