The best summer waterfalls would be Shepards Falls on the Lower Wind river. I wouldn't call these beginner falls as the second 22 footer is backed up by a jumbled manky 10 foot slide and then an 8 foot man made weir. But the first 15 footer is really fun and a big runnout.
Sunset Falls is by far the most straight forward falls you will find, followed with Horseshoe Falls just below on the same stretch.