Palouse Falls is located inside the State Park and offers obvious spectacular views. This is Washington's official State Waterfall and is one of the few remaining Ice Age flood plain waterfalls. You've likely seen pictures of the place somewhere online and when you make the trip your pretty much guaranteed to find a few photographers smashing the buttons on their cameras.
Palouse falls makes for a great picnic destination, is a great "stretch your legs" spot if you happen to be road tripping through the area, and offers some (although limited) camping options. With just a small handful of first come first serve camping sites you should definitely have a back up location ready. The parking lot and short look out trail is ADA accessible, and the wandering paths lead you all over the area including onto the top of the cliffs to the left of the waterfall.
You'll see some trails down below on the cliffs that are open or closed based on the river conditions. You'll find a gate at the trailhead for these lower paths, it will clearly either be locked or open. Be sure to follow the posted guidelines, there has been several deaths recently. Don't let that discourage you from a visit though, be smart on the paths and you'll easily be able to safely take in all the beauty that this dessert waterfall (is that a thing?) has to offer.
Here are a few helpful links to get you started. Be sure to share your adventures/pictures on our Facebook Group.