Which open air museum to pick: Tallinn, Riga, Vilnius, or Helsinki?

I visited the Estonian Open Air Museum in the Rocca al Mare area in early September and thoroughly enjoyed it--I went because my grandmother was Estonian, born and raised in what was then called Reval (now Tallinn) and I wanted a glimpse into life as she would have experienced in the early 1900s, though it covers earlier eras as well. It is quite spread out, and I was on foot--bikes can be rented. It is a lovely forested/park setting, and you come to different buildings and houses which you can explore and learn about life at that time. It borders on the Baltic and I went down to the water's edge and poked around for sea glass. Probably spent about 3 hours total--so if you take the bus, factor a 4-5 hr commitment, depending on your level of interest.

Getting there from Tallinn, now that was an adventure! I could not find the bus stop and anyone I asked for directions seemed to be Russian and all they'd do was look me up and down--not unpleasantly, just curious--and shrug. Finally I wandered over to a hotel in the modern Tallinn and found a bunch of taxis--again with the Russians! They also eyed me, conferred amongst themselves, and one said triumphantly, "I take you to Rocca al Mare!". I was not yet a seasoned traveler and yet felt perfectly fine getting into a cab alone with this guy--who did indeed take me straight there, saying in a reassuring voice several times along the way, "Rocca al Mare!". After the museum I had my bearings and walked over to their zoo, notable for the European birds of prey. I am happy to report the bus stop going back to Tallinn was right outside the zoo.

@christa, thank you so much for sharing this perspective. I really appreicate it. It is so useful to hear about the challenge with figuring out the bus to get there. We will definitely keep that in mind. And the whole story about the Russian taxi driver sounds like a scene from a movie!

I went to the one outside of Riga last fall. While it was interesting, it wasn’t earth-shatteringly so. I had a car and made it a stop between Riga and Sigulda. I loved Riga so I might say to spend your time in the city.

I also loved Rundale Palace and would not suggest skipping it. I spent several hours and could have stayed a little longer. Hill of Crosses took an hour at minimum - because there’s a bit of walking getting to it from the parking lot.

We visited the Estonian site last year in early May. Very nice location along the sea and a good choice for a half day activity. There are even some homes that give you insight to life in traditional Russian communities near the Estonian border. This site was not as large as either Skansen in Stockholm or the site in Copenhagen, but still plenty extensive. I have not been to the comparable sites in either Lithuania or Helsinki. It should be obvious that these kinds of places are very weather dependent as you are mostly outside and the trails are generally not paved. While we regularly take public transportation in Europe, we found that Bolt (a car service like Uber) was not expensive and a great time saver. That’s how we got to the open air site. We left Tallinn several times for its outskirts and Bolt was easy to use and fast to pick us up.

If you are in Tallinn for three days, this is worth a half day.

We visited the open air museum in Tallinn and in Lithuania and enjoyed them both.

It doesn’t sound like you have much time to spare if you will be doing Rundale and the Hill of Crosses on the same day. We visited the museum as a day trip from Vilnius by public transportation. We had no issues with the bus. We did a lot of walking. It is quite spread out. We probably spent 4-5 hours there.

We also had bus issues going to the open air museum in Tallinn. We went on the same day as a marathon in Tallinn and the bus routes were all messed up. We ended up taking a taxi there. The return bus was also messed up. The bus stop right outside the museum was closed for the day, but we were able to walk back to the main road and caught the bus there. We probably spent 3 hours there.

The two open air museums were similar. I think you could just pick one.

I’ve only been to Seurasaari and it was back in 2014. This link has my comments from then:
https://community.ricksteves.com/travel-forum/finland/seurasaari-open-air-folk-museum

Visited the one in Riga several times, even brought my kids there once (I have Latvian roots). Beautiful, large and well maintained museum in an amazing pine forest setting.
Also there are many original structures, not reconstructions.
Agree with other comments- forget the bus and take Bolt, the rides around the city are dirt cheap.