We did this as an out-and-back hike to the lower falls.  Only saw a couple of other people the whole time.  The hike was pretty steep and rocky, with a couple sections containing slippery enough rock that you needed to hang onto the guardrails provided.  I can only imagine how slippery these areas would be after a rain.  The waterfall at the end was worth it, though.  And though we couldn't jump in the water at the waterfall because of the delicate waterfall ecosystem, right below the falls is the Colorado River, which we swam around in for a while to cool off.

There are a couple nice views by the riverside, but other than that it's a lot of prairie hiking -- hot and dusty.   We didn't see anyone else along the trail except at points where the trail crossed the road.