This is a very attractive park with some fantastic scenery and nice, decently marked trails. ...though I would note when they say "strenuous" they mean it in regards to the "blue trail".
The trail around the cave itself isn't too bad, though the steps are pretty uneven. There were a number of children and senior citizens when I was there who had to take it all very slowly. However, the pay off is worth it. The day I went it was ninety degrees outside, but felt maybe 80 at most in the coolness of the gorge and in the shade of the cave and trees.
The cave itself is the main draw and well worth the visit. It's a gorgeous structure with lots of great photo ops. However, the crowds are pretty thick. Be careful near the edges lest unruly children try to push you over when they rush past.
I didn't hang around the cave itself much during my visit and instead did the six mile loop of blue trail to red trail. The blue trail is the prettier of the two, tracing the river bed with its myriad colors. The surrounding cliff faces are very attractive with windswept sedimentary striping, and worth seeing. The river, though, was particularly pretty.
During my trip, the water levels were very low, but the colors ridiculously vibrant. Each area of the river has a different color of sediment, changing its color completely with the levels so low. Where they mix, there's something of a rainbow effect that is just stunning.
Of course, the trade off is that the waterfalls are pretty much dried to nothing at the moment... Still, the rock faces they usually drop from are attractive in their own right and kids can still splash in the pool where it would normally cascade.
Though gorgeous and worth the trek, this path is pretty tricky. There are a number of areas that require you to scramble up or across rocks and even tree limbs. I did see a number of elderly people and folks with babies who didn't seem to be having much trouble, but I'm not sure I would recommend it for anyone who has problems with climbing or strenuous exercise. Even stairs, where they exist, can be ridiculously deep or tricky. So, use caution.
The other path up on the cliff - the red path - is.... more typical. It goes through the woods which is attractive, tranquil, and pleasant, but it's hard to find it too exciting after the beauty of the blue trail. It does lead to the Rose Lake dam, though, which is a very pretty vista indeed. Also, aside from one rather steep hill leading up from the Cedar Falls side, the path is level, even, and easy going.
The parking lot and visitor center at Old Man's Cave is, as of Summer 2012, under construction, but everything is still open. If you plan to do the round-trip hike, you can also park at Cedar Falls instead. read more