Getting there/ Getting around the Park
Changbaishan Park is pretty large and apart from the Heaven(ly) Lake at the top of the mountain there are plenty of other places to visit. To get to them, hop on one of the smaller brown buses. They shuttle people between the different locations. There are cordoned waiting areas, but no signs, so you will have to be brave and ask people where the bus you want is going.
These buses are free and if you have time it's definitely worth visiting the other places in the park
Waterfall and hotsprings (瀑布/温泉/pubu/wenquan)
To get here take a short bus ride (on a smaller bus) from where you catch the minivans to the peak. At the time of writing, these places were under redevelopment, and you couldn't get too close to the waterfall. Likewise the hiking route up to to the peak was closed. Anyway the waterfall is quite beautiful and you can have eggs and sweetcorn cooked in hot water from the mountain. You can also pay a small fee to dip your feet in the same hot waters flowing from the mountain.
Small Heaven(ly) Lake (小天池/xiaotianchi)
On the road between the waterfall and the main road up to the peak is small heaven(ly) lake. It's rich turquoise-green waters contrast beautifully with the white birch trees and triple waterfall. It's a great spot and walking around it is not very strenuous. Definitely worth stopping at before you leave or a great place to have a packed lunch.
Underground Forest (地下森林/dixiasenlin)
Again take one of the smaller buses to the Underground forest Forest, from either the waterfall and hot springs, small Heaven(ly) Lake or the main road up to the peak. Very well maintained paths and board walks take you through a lovely forest where you can see small gorges and waterfalls and view rushing gulleys. At one point on the path you are also rewarded with a beautiful view of the landscape melting away into green and blue. The walk can take anywhere between one and two hours, but its not very strenuous with only a small part uphill.