N'EX Round Trip Ticket & N’EX no.8

I will go to Kawaguchiko on the morning of Nov 18,2017. I found that there is Narita Express no.8 (or "LTD. EXP NARITA EXPRESS 8" in Hyperdia) that run directly from Narita Airport to Kawaguchiko on that day. I want to know that I can use "N'EX TOKYO Round Trip Ticket" for this train or not? Or I have to paid some additional cost? I think this train is the most convenience for my family to reach to Kawaguchiko.

https://www.jreast.co.jp/e/pass/nex_round.html#category05

Look "N'EX TOKYO Round Trip Ticket use area" section. The area for the Chuo line is until Takao, so you are not allowed to ride beyond Takao. Of course you can take NEX 8 up to Kawaguchiko if you pay the fee for Takao to Kawaguchiko. It should be 1723 yen for the fare and 1670 yen for the Express fee, the total is 3393 yen. Still the NEX round trip ticket is a bargain since the normal fare of the NEX 8 from Narita airport to Kawaguchiko is 7244 yen.

N'EX TOKYO Round Trip Ticket does not fully cover the fees for the whole route until Kawaguchiko Station.

Currently the route of
Narita Express 8
(starting from Narita Airport Station in Terminal 1)
and Narita Express 41 (heading to the airport)
is extended on Saturdays, Sundays and public holidays until the 26th of November to Kawaguchiko Station of Fujikyuko Railway (, which is also called as Fujikyu).

The JR section Takao -- Otsuki and the Fujikyuko section Otsuki -- Kawaguchiko are outside the usage area, so it seems you have to pay the fees for these sections.
http://www.jreast.co.jp/e/pass/nex_round.html
(The two Narita Express trains Nos. 8 and 41 both skip Takao Station.)

Total of estimated one-way additional fees
= 2450 yen per adult.
: 580 yen: JR basic fare for Takao -- Otsuki.
: 330 yen: Gap in JR Limited Express surcharges
between 2350 yen until Takao and 2680 yen until Otsuki.
: 1140 yen: Fujikyuko basic fare for Otsuki -- Kawaguchiko.
: 400 yen: Fujikyuko Express surcharge for Otsuki -- Kawaguchiko.

When you plan to make another long side trip by Day 3, to Nikko for example, JR TOKYO Wide Pass may be suitable.
http://www.jreast.co.jp/e/tokyowidepass/index.html

Unlike the N'EX discount ticket, this pass can cover Fujikyuko basic fares Express surcharges.
Like the N'EX discount ticket, only foreign passport holders are eligible for this pass.

For your way back to NRT, it depends on the location of your starting point what transportation modes and passes or discount tickets may be a good choice.

The word "and" is missing in my previous response.
NOT: Fujikyuko basic fares Express surcharges.
BUT: Fujikyuko basic fares and Express surcharges.

In a case where a JR Limited Express surcharge is required separately for the section Takao -- Otsuki, the amount is 1270 yen (on the day of your ride), so the total of JR and Fujikyuko surcharges is 1670 yen, as frog1954 says.

The amount of JR Limited Express surcharge is decided by the distance.
You travel until Takao then beyond Takao until Otsuki continuously on the same Narita Express train, and N'EX TOKYO Round Trip Ticket is valid until Takao.
So, I suppose you pay for this JR-East Limited Express train service just the gap in the amount of the Limited Express surcharge(s).

Since N'EX TOKYO Round Trip Ticket is a paper ticket, JR IC basic fare does not apply when you make adjustment with an IC transportation card such as a Suica card.
Therefore the amount of the additional JR basic fare which you pay is not 583 yen but 580 yen, and the total of JR and Fujikyuko basic fares is 1720 yen, not 1723 yen as frog1954 says.

Thank you very much for "frog1954" and " omotenashi". Both of you are real "Japan Omotenashi".

Just keep in mind there is only ONE of these trains each way on Saturday and Sunday only, and it takes 3.5 hours. It's not really any faster than taking the N'EX to Shinjuku or Tokyo station and then transferring to a Bus.

A long time since I rode that train on a rail pass, but the Fuji Kyuko section supplement needed to be paid on the train - there was not an option to do a fare adjustment or pay at the terminal station.

Thank you for Me2 and JapanCustomTours.

I may use Tokyo Wide Pass for the ride on N'EX no.8 :
Cons : High Cost 10,000 Yen when compare with
- Direct Bus from Narita Airport
- N'EX to Shinjuku then Bus to Kawaguchiko
- Other Transport to Shinjuku then use "Fuji Hakone Pass"
Pros : 1) Most convenience
- Direct no transfer
- No need to move big luggage : I found that it difficult to find escalator or lift in some stations in japan (last year I have problem with stairs in Shibuya station, I heard that this year it already has escalator, yeah!).
2) Faster
- I love photography, day time in late autumn is very short : more time is more chance for photography.
3) Most relax
4) Able to use for another destination
5) Bus to Kawaguchiko may already full in the time that I need, I may have to waiting for the bus 2-3 hours or go by ordinary train that have to transfer many times with big luggage.