There used to be a much better view of these falls from a bridge that crossed the river below the power house. It was washed out twice in the same year by floods so they decided to not bother rebuilding it and cut off the most interesting part of the walkway and moved the trail to the top of the chasm. It's too bad because it's much less interesting to walk 100 feet above the water and look down on all the cool stuff at the water's edge. Back in the late 80s when I had last visited, your admission ticket got you the walk down the river, then a boat trip the rest of the way, where a bus took you back to the main parking area. Now, you walk the whole way down unless you buy an extra ticket to take a raft or tube ride down a longer section of the river.
These shots were taken from the bridge that carries the road over the river, it's free to see this view.
Once you get on the trail and walk further down the chasm, you can look back up and see the falls and the road bridge
To be truthful, if all you want to see is the falls, then just park at the free area before the bridge and use the pedestrian access to view the falls. If you get there when there are only a few people, setting up a tripod would probably not be a problem. I honestly don't remember if I did or not, I just remember there were a lot of people and traffic going past, vibrating the bridge and it was brutally hot that day.
