The mill is not very big. You have to take a guided tour to visit it. The tour lasted less than an hour, including a short movie shot during the last summer of operations before the mill was closed. The movie is old, but it's good, and really brought into life what I saw on the tour.

The amount of people allowed on each tour is quite small. There were about 20 of us, and they already split us into two groups because there were so many of us (our group saw the movie after the tour, the other group started with the movie). They recommend prebooking on their website. Tours in other languages than Finnish need to be booked ahead, but when I visited, someone English-speaking just walked up to join the tour and the guide shared some of the information in English.

The mill has been kept in the condition it was in when they closed and it is well maintained. I assume that as there are not that much visitors, the owner UPM-Kymmene puts a lot of their own money into maintaining the museum. It was interesting to see how rudimentary the process of cardboard manufacturing was back in the days.

There are also other buildings in the area. You can get in some of them, but they are quick to scan through. There are also prehistoric rock paintings that can be seen from a small platform built next to the parking lot.

I'd say Verla is still off the beaten path. The somewhat remote location must contribute to that. Sure, it can be reached by car, but a typical tourist probably doesn't end up in the area, so you have to drive there just for the purpose of visiting Verla. I went there by bus. There are a whopping 4 buses a week there and back from Kouvola (bus number 15 of Kouvola public transport): on Saturdays and Sundays there's a morning bus and an afternoon bus. On weekdays, there is no bus service. At least this summer the bus timetable was made so that the morning bus left about 1.5 hours at Verla and the afternoon bus about 2 hours (or if you take the morning bus there and the afternoon bus back, you would have the full day there, but I believe it would be too long). I took the morning bus, so I had time to take the tour and scan the rest of the area quickly. I had prebooked my tour at the mill to make sure that I could get on the only one that fits in the slot the buses allow. The bus departed from the railway station in Kouvola and went past the Veturi shopping mall, where some of the long-distance coaches stop. I left Helsinki on a train departing a bit after 8 AM and was back around 4 PM (I had lunch in Kouvola after getting back from Verla).