I'm finalizing my itinerary for Palau at the moment. A big remaining question mark is behind a visit to the TWHS of the Yapese Stone Money Quarry sites. It includes two archaeological sites in Palau, named 'Uet el Daob ma Uet el Beluu' and 'Chelechol ra Orrak'. Looking at the provided GPS coordinates, both are fairly close to the main Island in Airai State. But I have no idea about transportation or accessibility of the sites.

Anyone who has researched this before and found some answers?

I was in Palau in November and have visited all 4 proposals from TWHL.
I reached only one site from Yapese Stone Money Quarr - Chelechol ra Orrak, they call it Metuker er a Bisech. The site is located in a small island belonging to Airai State. At the time I was there, only one tourist agent was organizing 2-hour trip to the site (it could be shorter or longer depending of your climbing skills). I do not remember their name, but it is easy to find them because the office is located just under the big bridge connecting Koror to Babeldaob (the big island); it'll be on your left hand side when you drive from Koror - just cross the bridge and then make a U-turn, choosing the road that goes under the bridge; this is the last building on your right now.
You will hear that at least two people are needed to organize a boat for that trip, but if you insist and show how much you'd love to see "this unique Palauan treasure" they do it only for you. That's what happen to me; we agreed the day, the time. The price is fix: 35 USD for the trip plus 25 USD for kind of a permit to visit historical places in Airai state. If you have paid it already in Airai State Office, you'll just have to pay only for the tour.
After 25 minutes boat trip you land at a provisional harbour, and then you have to climb up for another 20 minutes. The path is steep, but marked with a yellow handrail, sometimes broken. As this is a jungle and not many people are visiting the site, you'd better have good shoes and long trousers. When I was there the humidity reached almost 100%, lots of small insects in the air and on the ground, so it was not very pleasant experience but worthy! Don't count on a guide! The man who brought me there stayed in the boat. There are some informative boards, but old I think and it was really difficult to see any explanations.
First you reach an example of a big stone money that was broken when transported from the quarry, that's why they left it here. It is surrounded by a yellow fence. It is really big! And it is here that I started wondering: why? why they were doing it? If you follow the yellow handrail (there is no visible path anymore, so go through the bushes and fallen trees) for another 10 minutes, you'll reach the quarry itself - just two big caves one opposite the other. There's another info board illustrating how the whole process looked. And if you follow the yellow handrail for another 20 minutes, going up, very steep (no trace of a path at all, I had the impression it was longer), you can see one more big money, unfinished.
Then I got back to the boat and we came back to the starting point (the office). My boatman showed me some relics from WWII, some mussels farm and also one cave we got into. And that's it.

Thanks a lot! I heard about Metuker er a Bisech, but wasn't sure whether it is the same site.

P.S.
And nice review too, with a photo of discarded stone money. Another story about it is here: http://www.traveladventures.org/continents/oceania/metuker-ra-bisech-stone-money-quar ry.html

P.P.S.
Still a bit in doubt if this is the right location. Metuker er a Bisech lies on Metukerabisech Island, while Chelechol ra Orrak is on Korak Island. See this list, there are several quarry sites: http://www.mechanglagoon.com/2016/08/airai-state-and-its-attraction-to.html

There is no doubt that these (Metuker er a Bisech and Chelechol ra Orrak) are 2 different places and that, for some reason Palau has NOT included Metuker er a Bisech within its T List site proposal as it currently stands
(A problem in searching on any of these names is that there are considerable spelling variations in converting from Palauan to "English" - from here on I will refer to the 2 sites simply as Metuk and Chelechol!!)
Also that Metuk has been "developed" for tourists with railings etc as described by Warwass whilst the situation regarding Chelechol is unclear - at least from any searches on the Web I have been able to make.

For the fact that they are different sites see
a. This official document of 2010 - "Airai Master Plan". www.palauconservation.org/cms/images/stories/.../Airai_Master_Land_Use_Plan.pdf
Section 2.3.1 lists 15 of the state's historic assets. Metuk is number 3 and Chelechol number 13. It also lists Metuk as being one of the 6 which had been "restored" (in 1993 and 1997). Notice also that the "village"/area address differs within the state!
b. This Palau travel site also lists the 2 sites separately - http://www.palau-travelguide.com/category/things-to-do-in-palau/palau-things-to-do-in -airai/

This rather nice site with map places a pointer with a mouse-over title for each of the sites - Chelechol is one of the 3 pointers on the island of "Orrak" approx in the centre and Metuk is on the peninsular (it may just be an "island" - Google Earth seems to show a possible man-made (??) cut at one point) to the west (the more northerly of the 2 pointers - https://www.mbendi.com/attraction/chelechol-ra-orrak-burial-site-1000-bc-917777

This page from Palau Travel Guide also contains a map (scroll down) showing the location of each site - http://www.palau-travelguide.com/metuker-ra-bisech---yapese-quarried-sone-money-site- 37.html

This site contains references to BOTH sites and has a detailed map of Metuk together with a photo of Orrak Island - (which it describes as "probably the best quarry site where you can still see the remains and the platforms and the living areas where they were.") - http://www.pacificworlds.com/palau/native/native5.cfm

Metuk seems to be offered as a tour but I can find no mention of any tour to Orrak. Here is a report by someone else visiting Metuk - different prices from those of Warwass but similar details regarding need for permits etc etc - http://www.traveladventures.org/continents/oceania/metuker-ra-bisech-stone-money-quar ry.html
Note that their boat (and that of Warwass) departs from the bridge connecting Koror and Babeldaob. Metuk is "across the bay" from there towards the end of the peninsular. To get to Korak you would need to depart from the road which ends at the Biota Marine Life nursery (see Google maps) a bit beyond the US embassy on the other side of the airport and right round the peninsular and across another bay so any boat from the same company and location would have a lot further to go to get to Chelechol.

Which leaves the other T List site of 'Uet el Doab ma Uet el Beluu'!! This doesn't get even the same mention as Metuk on the Visit Palau web site but is mentioned in the Airai Master plan as historic site No 8 (also undeveloped at the time). All I can say is that, if you feed the UNESCO coordinates into GoogleMaps you finish up on Korak island!!!

Thanks for the further research, Solivagant.
I think getting to Korak warrants a close inspection 'on the ground' while I am there.

Of course we also do not know exactly how the revised Yapese disk money nomination will look like. Maybe additional quarry locations will be added, although that would complicate the management issues even more.
The nomination file must be almost ready now, for submission before Feb 2017.

It was an interesting subject -even if I can never be "bothered" to go there! I hadn't previously realised that ALL the Yapese stone money came from Palau and was transported at great risk and loss of life the 250 miles across the ocean to Yap. See - http://news.bbc.co.uk/hi/english/static/road_to_riches/prog2/tharngan.stm

I have checked it with a man from from Palau Preservation Office at the Ministry of Cultural Affairs - I went to Ministry of Education (the biggest building on the main street of Koror) and they contacted me with him. He told me that The Metuker er a Bisech site is to be included to the nomination file together with other few. You can also contact them through their Facebook: https://www.facebook.com/Bureau-of-Cultural-Historical-PreservationPalau-HPO-51637738 5135366/.

The nomination file was not ready yet, they were still looking for some help from Australia and/or USA.

If you look at the picture and at the map at http://www.palau-travelguide.com/chelechol-er-a-orrak-airai-babeldaob-palau-209.html you'll see that the place Chelechol er a Orrak is located by the sea and not in the middle of the island where there's no access! So the location is wrong.

It took four months to get a reply to my e-mail sent in March, but finally I've got it and what's there:
1. Yapease Quarry Sites (Micronesia, Palau) - the nomination file is not completed, it looks more complicated than they thought; still waiting for international help;
2. At the same time local authorities started second nomination dossier for Ngebedech Terraces; the draft version should be ready at the beginning of 2018. ( I have no idea what "draft version" means.)