Kachi Kachi Ropeway [ カチカチ山ロープウェイ ] is a cable car you can take to the top of Mount Tenjo [ 天上山公園 ] to have a view of Mount Fuji on one side and Lake Kawaguchi on the other. Instead of taking the cable car, you can choose do a short hike up. The entrance for the hike is just next to the lake, about a 10-minute walk from Kawaguchiko Station [ 河口湖駅 ]. It's only about 30 minutes to the top if you don't take any breaks. The trail is a bit steep but not difficult as it's just steps all the way up. In the autumn, it's quite beautiful.
It takes just 10 minutes to the first view point for your photo-op with Mount Fuji. You can also see the amusement park, Fuji-Q Highland. There are benches to sit and have a short break.
From the first view point, it's about another 20 minutes to the top where the ropeway ends.
There's a shop up top selling souvenirs as well as food and drinks. The soft serve ice cream up there is pretty good!
There is also a small shrine where you can leave 100 yen to buy 2 ceramic plates and try to throw it in the circle for love and good luck. Aim high and throw hard!
If you can read Japanese, you will see a board with the story of a rabbit and a Japanese raccoon dog, or tanuki, that was set here.
Kachi Kachi Ropeway has more information.