Contrary to what the WARNING in the description above says, the trail is now open all the way from the Canyon Trail Kiosk (highest point) to the Boardwalk Kiosk (lowest point), a distance of 3 miles, and that is exactly the direction I hiked it. Then I turned around and went back up.
As others have said, most, but not all, of the steep steps are in the 1 mile Canyon Trail, which has the largest overall elevation change from 920 feet to 680 feet. In this section, however, the accumulated gain and loss is greater as the trail and steps meander up and down several times.
The Canyon Trail then connects to the 1.5 mile Upper Panther Trail. It has a few steep sections but also some level sections. This section ranges from 700 feet down to 530 feet, but again the accumulated gain and loss is a bit more as there are some uphill stretches.
The Upper Panther Trail connects to the 0.5 mile Lower Panther Trail, which terminates at the Boardwalk Kiosk. This trail is fairly flat, only ranging from 560 feet to 520 feet.
Had great weather and quite a few people were out on the trail, but I had a fair amount of solitude as well. There wasn't much water in the creek but it was still a very pleasant day. Thanks to all the people from River Place and elsewhere that worked long and hard to get this trail open again!
Starting the out and back at the Boardwalk Kiosk is easier as you don't have to finish on the steep steps of Canyon Trail as I chose to do.
And if you only want to go one way, you will need to have transportation parked at both trailheads.