The typical tourist takes a day trip from Shinjuku to visit the Fuji Five Lakes. To beat them, do not start the trip from Tokyo. I started from Numazu although an even better alternative was Gotemba, but the budget hotel chain I liked didn't have a choice there. I got a Mt. Fuji-Shizuoka Area Tourist Pass Mini, which costs 5080 yen and covers JR lines in Shizuoka and Fujikyu buses that take an hour from Gotemba to Kawaguchiko.
At This Stop
Mount Fuji can be elusive at times and the tourist literature says the clearest times are early morning or sunset. Even when it is blue sky all around you, there may be a wandering cloud that covers up the top. Research the weather forecast the night before and watch the skies as you start your day.
You should easily spot many other tourists at Kawaguchiko station. For lunch, head across the street where you should see a long line for lunch at Hoto Fudo, a local institution. Hoto is a noodle dish cooked in a big pot. This restaurant only offers 1 kind, vegetarian. You get a generous portion of different vegetables, a thick slice of pumpkin, and supposedly some miso paste but I couldn't taste much of it. This would be a very warm and decently-filling meal before you continue up another mountain.
After filling up, you can walk downhill towards Kawaguchi Lake for a cruise or the ropeway.
The Mount Fuji Panoramic Ropeway makes a short ascent up Mount Tenjo to an observation area with great views of Fuji. I arrived with a huge line in front, and the audio announcement said a 20 minute wait is needed. I suggest you buy a one-way to ropeway up, then hike down.
The ropeway operates every few minutes and staff pack the cars up like sardines for the short trip.
From here, gaze at Fuji's beauty.
Upon exiting the ropeway, you will see a huge crowd at the ledge taking pictures of themselves and Fuji. Don't get tempted. Keep going beyond the service building where there is an arch with a path heading further into the mountains. The dirt path heads uphill towards a new observation area higher up with an even better view.
A line of tourists obeying the 1 person at a time principle would allow a more exclusive photo experience. However, given this is a dirt path, it can get extremely muddy, and although the previous few days before my visit were dry, I had mud all over my shoes and on my pants by the end of the ordeal. Still worth it though ...
Satisfied, I wasn't in the mood to wait in line for the ropeway. The downhill hike is not too difficult although it is not paved but mostly dirt tracks with defined staircases. It gets slightly icy during the winter but you are rewarded with more views of Fuji without the crowds. The official guidance says a 40-minute hike but I thought it was faster than that.
By now, it should be mid-afternoon and you don't have much time left for your day trip. Unless you are visiting during the flower season, skip the lakeside parks and go back to the train station to board a bus to either the Wind or Ice Cave. You probably don't have time to visit both. The Fujikyu bus to both caves, and onwards to Shin-Fuji station, are covered by your pass. However, I'm not sure whether the Blue or Green sightseeing buses that get you there are, so best to study the bus schedule beforehand to catch the exact frequency.