NewbieRunner

"Holiday Kaisoku Fujisan 1" turns out to be more popular than expected. In order to avoid having to go to the station very early to secure seats or to risk having to stand for 2+ hours here is a revised (and definitive) plan. I have bought tickets/reserved seats for all 25 people listed in post #370.

Depart Shinjuku 08:30 "Limited Express Azusa 7" (leaves from platform 9)
Arrive Otsuki 09:38
Depart Otsuki 09:59
Arrive Kawaguchiko 11:00
(The rest of the schedule remains as before)
Leave Kawaguchiko 12:10
Arrive Gotemba at 13:20
Leave Gotemba 13:40
Arrive Tōgendai 14:13

Once we arrive at Tōgendai on the shore of Lake Ashinoko, the rest of the trip could be quite flexible as we will be on the popular tourist trail. The ropeway to Sōunzan takes just 24 minutes but we will stop at Owakudani to look at volcanic activities on the way. From Sōunzan to Gōra takes 10 minutes by Hakone Cablecar (runs every 15 minutes) and from Gōra to Hakone Yumoto takes 40 minutes by Hakone Mountain Railway which also runs every 15 minutes or so. From Hakone Yumoto back to Shinjuku will take 1hr30min to 2hr+ and there are frequent trains.

I have bought tickets for the following and will collect the total of 3,500 yen from each person for:
Shinjuku-Otsuki Limited Express charge and reserved seat: 1,450 yen
Gotemba-Tōgendai Odakyu bus with reserved seat: 1,020 yen
Hakone Ropeway group fare Tōgendai-Sōunzan: 1,030 yen

Each person will have to pay the following on the day:
Shinjuku-Otsuki JR train: 1,317 yen
Otsuki-Kawaguchiko Fujikyu train: 1,140 yen **
Kawaguchiko-Gotemba Fujikyu bus: 1,510 yen
Sōunzan-Hakone Yumoto cable car & mountain railway: 820 yen
Hakone Yumoto-Shinjuku: varies between 1,184 yen to 4,050 yen

You should be able to use your Suica on all the above except the Fujikyu train between Otsuki and Kawaguchiko. Tickets for this section may only be bought in Otsuki. It looks like you can use a Suica on Fujikyu bus between Kawaguchiko and Gotemba but their website isn't clear. Be prepared in case you have to pay cash.

Since the recent consumption tax increase some transport companies started charging different fares for payments using IC cards such as Suica and cash. Cash prices are rounded up to the nearest 10 yen while you may be charged a few yen less by using a Suica!