The ape caves are AWESOME! There are two different parts of the caves: the upper and lower caves. When you take the stairs down the lower caves are in front of you and the upper caves are behind the staircase. The lower caves are super spacious and easy to hike. There are always a lot of kids/field trips going on in there, so expect company!
For more of a challenge go to the upper caves. This tunnel actually has an exit at the end of it, unlike the lower caves. You will find yourself climbing over large boulder fields and squeezing between small spaces. If you get claustrophobic, prepare yourself for this one! Unless your kids are little badasses I wouldn’t recommend taking them down this route.
Make sure everyone in your group brings a headlamp, she extra batteries, and a down coat/sweater because it gets pretty cold down there.
Fun Fact! The Ape Cave was formed over 2000 years ago from lava flowing down Mt. St Helens.