Transportation from Shinjuku to Haneda

Hi
Before anyone replies to use HYPERDIA I already have!
All the options suggest 3 transfers!
I am considering 2 options

1 checking out early and leaving our luggage at Hamamatsucho station ( for the monorail to Haneda) This would hopefully give us a few stress free hours before heading to Haneda

2 Sending our luggage separately to Haneda when we check out from our hotel

Do either of these options make sense?

1 transfer! Yamanote to Shinagawa and Kikuyus to Haneda....

I despise tablets! Keikyu to Haneda....

Opinions may vary but let me share based on my experiences, not particularly for Shinjuku to Haneda route. A little comment based on John's reply above, it only requires 1 transfer at Shinagawa. For some reason, Hyperdia tends to suggest the routes through Hamamatsucho.

Option 1: This will depend on how many luggages you have, the timing, and where you'll go on that day. You need to travel to Shinagawa, find available lockers, travel to another place for sightseeing, and travel back to Shinagawa. Spare ample of time to collect the luggage (finding the locker, going to the platform) before heading to Keikyu platform. I'm not sure if all platforms at Shinjuku has escalator/lift.

Option 2: This would be the most hassle-free option, but both me and my partner are still reluctant in case there's risk the luggage doesn't reach on time. Nevertheless any people has used the luggage forwarding service with great result so it might work well for you.

For some reason, Hyperdia tends to suggest the routes through Hamamatsucho.

Hyperdia has two stations at Haneda's international terminal: "International Building" is the Tokyo Monorail station, and "International Terminal" is the Keikyu station, reflecting the official name of each station. So if you choose "International Building", it will prefer routes via Hamamatsucho and the Tokyo Monorail. If you want to go through Shinagawa and the Keikyu line, choose "International Terminal".

(By the way, through Hamamatsucho is only one transfer as well, from the Yamanote to the Monorail, and it is JR Pass-compatible.)

Ah, no wonder. I've been wondering why Haneda and Narita at Hyperdia have the "Terminal" and "Building" option. That clarifies. Thank you!

At Narita it is a bit different; "Narita Airport Terminal 1/2" are the train stations for both JR and Keisei, while "Narita International Airport Terminal 1/2/3" are for flights.

To option 2: regardless of number of transfers sending your luggage CAN be a good option if you have large/heavy/many luggage or want a specially hassle free trip. I used it a few times to Narita and never had any problems.

Enjoy your trip to Japan!

Luggage cannot be sent to the airport via Yamato on the same day of the flight.

(By the way, through Hamamatsucho is only one transfer as well, from the Yamanote to the Monorail, and it is JR Pass-compatible.)

However...

It is true that if you do a Hyperdia search from Shinjuku (JR) to Haneda Int'l Building (Tokyo Monorail), the top result can sometimes (depending on your departure date/time settings) be a route with two transfers (first Chuo line to Kanda and then Yamanote to Hamamatsucho).

Example here (depature today at 21:00): http://www.hyperdia.com/cgi/en/search.html?dep_node=SHINJUKU(JR)&arv_n...

The first three results are Chuo+Yamanote, and the "obvious" Yamanote-only route is only 4th. There is a reason for that, however: the first three are faster. Yeah, they are faster by just one minute, but they are faster, and by default Hyperdia prioritises speed over everything else. But if you want to get the route with the fewest transfers, it is easy: just choose "Transfer" in the "Order" box in the search settings.

Limousine bus is zero stops and only 1200 yen

https://www.limousinebus.co.jp/en/bus_services/haneda/shinjuku.html

^^^^ I meant zero transfers, not zero stops. It stops at several locations.

I would recommend to take the limousine bus instead of train ride. Reason being train tends to be really crowded (morning/ evening) especially when taking Yamanote line from Shinjuku.
My experience was a crowded morning at around 8am with my luggage. The queue at the station was really long and I had to miss a couple to board the train at Shinjuku. Shortly after, I got squeezed to a corner as passengers started to board from other stations.
Not a fun experience with luggage to Haneda. :D

Thing is, apparently OP does not want to go straight from Shinjuku to HND, but to go somewhere, leave their luggage for some time, and go to HND later.

It seems like you want to do some last minute shopping before flying out of Haneda. My last trip to Japan was in December and I did just what you have mentioned as option 1, But I had a large 28 inch luggage and a 18 inch luggage. I actually had my 28 inch luggage full days ago, so I left it Hamamatsucho station in those paid coin op lockers over night (do note it's usually upto 3 days only), and collect it on my way to Haneda problem free.