Brian Burgit recommends a wet and wild day hike. Looks great.
Falls Trail: difficult hiking
The full loop of this trail is 7.2 miles if hiking both the upper and lower sections. To see most of the waterfalls, a 3.2-mile loop can be taken by going on Highland Trail and the Glen Leigh and Ganoga Glen sides of the trail.
The trails follow along 21 beautiful waterfalls ranging in heights from 11-feet to 94-feet. The scenery is well worth the effort, however, the terrain is rocky, can be slippery, and descends steeply on both the Ganoga and Glen Leigh sides.
The Falls Trail is closed in the winter except for properly equipped ice climbers and hikers.
details – Pennsylvania State Parks – Ricketts Glen Trails – PA DCNR
besthike.com 
I heartily recommend this hike to anyone able to handle the grade! Basically, if you hike the triangular area, with the spur I describe below, it’s about 3.5 miles (7 if hiking the whole thing from Route 118).
I recommend doing it like this:
-Start from the Lake Rose parking lot.
– Follow the Highland Trail, enjoying Midway Crevasse enroute (great group-photo spot).
– Do down Glen Leigh.
– At Waters Meet, continue downstream to see the three waterfalls shortly below; then reverse back to Waters Meet.
[Unofficial information I’m not personally recommending: at the third (most downstream) fall of these three, Murray Reynolds, folks often jump off the cliff by the trail into the splash pool below the fall. Be sure to check the pool first to make sure there are no obstacles there, such as a sunken log.]
– Climb up Ganoga Glen, returning to your starting point.
The triangular hike I’ve just described basically amounts to a one-mile downhill, a one-mile uphill, and about 1 1/2 miles of basically level walking.
Please be sure also to visit Adams Fall (just downstream of Route 118): IMHO this is the prettiest fall in the park! 🙂
And there’s yet another fall underneath the highway bridge.
If you’ve done all the above, you’ll see all 24 waterfalls!
(There’s also usually a one-foot-high mini fall in a small grotto on the left just as you’re leaving the Lake Rose parking lot.)
(And for those who can’t handle the main slopes, there’s a side trail to Ganoga Fall (at 94′, the highest) if from Lake Rose you take the Ganoga Glen Trail, bear right onto the Beaver Dam Trail, and then take the next left turn. )
Enjoy! 🙂
Bruce
Thanks for the tips, Bruce.
I hope to get there over the next couple of years. (Missed my chance in 2007, darn it.)