Amazing route. Generally you start on WI3 right of center and traverse right and climbing the right side of the falls. As with any ice, conditions vary from year to year but when I did it in 09 the crux was the super thin ice at the top. When the falls are completely in you have many different climbing options from WI3 to the WI4+ we did.
Drive as if you are heading to Crystal Ski area. About 30mins outside of Enumclaw there is a pull out on the right for the falls. Park there. Hardest part is getting across the river. We found an ice damn up river but crossing conditions will vary from year to year. If you go climbers right there are trees you can rap off of. Another option is to go climbers right another 10min of the rap anchors and descend a moderate gully down.
Screws and a long sling for the tree at the top.