Having seen most of Poland's WHS some random thoughts on them. Not sure where I should write a full review:

Wooden Churches and Tserkvas:
* Surprisingly nice. Would have loved to see more. If only I had a car, it hadn't been raining ...
* If you just want to tick this off, going to Gorlice is the best choice (1 Tserkva, 2 Churches nearby). There is a direct bus from Krakow. And you can continue to Rzeszow and from there further east (Zamosc). Locally, I would just get a cab (120 Zloty to see all three).
* As stated by others, opening times are really hard to discern. I entered 2, I saw 4.
* If you are in Cracow the easiest visit is to Debne (near Zakopane). Unless you hit your head while hiking in the Carpathians and have to go to the ER instead. The church (at least it says so on their web site) is only open if it's not raining. You may need to get a cab in Nowy Targ

Zamosc:
* A connection to Lwiw can be made by going by local bus to Tomaszow Lubelski (every 30min nearby the main bus station). From there a bus to Lwiw is available. It does not depart from the amin bus station but from where the local bus drops you (Armii Krajowej Parking). Be prepared: You will spend 1-2h at the border. I got my ticket at infobus.eu.
* If you get off at Schowkwa, you can see another Tserkva. From there frequent local busses will take you to Lwiw. The Schowkwa is probably open for service during evening (5:30h). And Schowkwa itself is nice.

Tentative - Tarnowskie Gory Lead-Silver Mine and its Underground Water Management System
* There is a train station in town, but from there it's still quite a walk to the mine.
* The mine is rather modern. I don't see why this should be inscribed next year.

Useful links:
* https://en.e-podroznik.pl/ -> Local bus connections. Not complete, but way better than google maps. I recommend getting the app.

I thought I would mention that if anyone has imminent plans to visit the 2019 inscription, "Krzemionki prehistoric striped flint mining region" site near Ostrowiec, they might want to postpone those for a while. I was there yesterday, and had a rather disappointing visit.

The official Website for the Site mentiions that the most interesting part for visitors, the underground mine route is currently closed until 2021, not for the pandemic, but for "renovations." Allright, I thought, I will at least go to the museum and see some of the mine entrances from above ground. When I arrived, I soon learned that the entire site was closed (this time due to covid) even though the Website doesn't mention that. I was told the they expect the whole site to be open again this October, but I wouldn't count on that.

Next I thought I would sneak along the Nature Trail, where I might get a glimpse of some mine entrance through the bushes. However, in only a minute or two I came across two women walking out, one staff member, and one who just gave a talk on medicinal plants. They reiterated that the Site was closed, and proceeded to shoo me out of there. But when noticing the disappointment on my face, the staff member agreed to unlock the main exhibit of the museum for a few minutes, so I could look inside, which I very much appreciated. Paradoxically, I had never given much thought to the mineral Flint until a day or two earlier, in preparation for that visit, and was amazed to discover that the geochemistry of Flint formation is very similar to the processes we researched during my former professional life, so I had an extra motivation to see something of this particular mining site. It was a low-quality visit, to be sure, but under the circumstances, I am counting it.

Getting in to Poland has been my first crossing of a now-open border that had previously been closed, and it felt good. Though, technically, I am not 100% sure I should have been let in, since I am not an EU citizen, but there were no document checks at all when I arrived by ferry from Sweden. Finally moving again, I have picked up four new WHSs, and one T-site, with five more coming in the next week or so (notably, I have decided to skip Auschwitz, since with the wonderful way the first half of 2020 has gone, I don't really feel in the mood for that kind of site right now.)

I hope the rest of you will be able to go somewhere soon, and that the Sites will actually be open when you do! ;-)

Sorry, you ventured there without getting the full experience.

I actually wrote them as I was considering myself. The website was inconclusive. Reply was that they are closed for 2020. Personally, I detest it if a site gets inscribed and then you do the renovations. If they are required for site upkeep, you should do those before inscription. And Unesco should not approve of adding the site. Or wait a few yearsand give people a chance to visit the site for a few years and renovate when the novelty wears off.

When we visited Bialowieza a few years ago much of the frontier with Belarus was "open" in the sense of there being no fences etc so animals could cross to and fro. At Stare Masiewo we walked right up to the unfenced frontier in uninhabited and unguarded forest with nothing to stop us crossing apart from a Notice board warning us not to approach within 15 m (there may or may not have been cameras watching us)! There is a "Buffalo feeding station" there for the use of animals from both sides of the frontier.

Does any Forum member from Poland (or elsewhere) know how this is changing as a result of the current Migrant issue with Belarus? Is the frontier inside the Core Zone being fenced with barbed wire with the inevitable impact on wild life passage and are Polish/Belarussian troops operating inside the core area? One presumes that, since Lukashenko's aim is to get as many migrants across the border as possible, he would have targetted this umanned frontier even if it is within a WHS? If the EU Eastern frontier is to become a long term "hotspot" then this seems likely to have a permanent impact on the Forest. Also - what impact is this having on "tourism" - if troops are operating to prevent migrants crossing one presumes that tourists wondering in and out of the forest near the frontier will not be welcome.

This is an interesting article about the progress of 2 Polish sites in the pipeline:
https://www-zawszepomorze-pl.translate.goog/centrum-gdyni-na-liscie-unesco-wniosek-do-poprawki?_x_tr_sl=pl&_x_tr_tl=en&_x_tr_hl=nl&_x_tr_pto=wapp

It gives the reason why the Gdynia nomination last year was deemed incomplete ("the objections concerned the quality of the topographic map and the failure to grant a license to UNESCO for the use of photographic materials constituting illustrations for the text of the application").
And why the Gdansk Shipyard was postponed indefinitely in 2021 ("after negative positions on the Polish candidacy were expressed by representatives of, among others, China and Russia"). It's unsure whether they will try again in 2024.

An update from Poland (thanks Andrzej, for sharing!):
https://nid.pl/unesco-polish-experience/

They are participating in serial nominations of:

PAPER MILLS FROM THE PRE-INDUSTRIAL ERA
Six partners from Poland, the Czech Republic, Germany, Spain, and Italy

BEGINNINGS OF PETROLEUM EXTRACTION
Three partners from Poland, Germany and Canada
The proposed international serial property nomination includes three museums/oil mines: the Oil Mine in Bóbrka (Poland), the Oil Mine in Wietze (Germany), and the Oil Mine in Oil Springs, Ontario (Canada). These are evidence of petroleum's leading role and the development of mining extraction of that raw material as the driving force of another industrial revolution in humankind's history.

MOUNTAIN FORTRESSES
Five partners from Poland, Italy and Germany
The proposed international serial property nomination includes a group of five mountain strongholds located in three countries: Srebrna Góra Stronghold (Poland), the Königstein Fortress (Germany) and the Fenestrelle, Rocca d'Anfo and Fort Bard Fortresses (Italy), which are evidence of the European phenomenon of the development of modern mountain fortifications, the transformation of mountain ranges in a purely military nature, and pioneering adaptations in extremely harsh local environmental conditions and the need of broad landscape exposure.

FUTURE:
Presently, Poland is actively preparing for the execution of the next international serial nominations, including Works by Erich Mendelsohn (Poland, Germany, Israel, U.S.A); Graduation Towers (Ciechocinek), 19th-century factory towns (Zyrardów, Lódz), Water transportation canals (Augustów), and hard coal heritage (Zabrze).