Among the six sites listed as Dacian Fortresses, I visited Sarmizegetusa Regia in May 2023, by car, on my way from Sibiu to Budapest, Hungary (the rest of the ruins are also nearby, but I didn't have more time). If you don't have a car, you can find an organised tour from Sibiu, or take a bus to Orăștie and try to find a taxi there (or maybe hitchhike... it used to be a popular way of getting around in Romania, but this time I didn't see any hitchhikers by the road). From the A1 highway it takes about 50 minutes to arrive to the parking lot of Sarmizegetusa Regia, the road is good, then you need to walk (slightly uphill) about 1 km. The entrance fee is 15 lei, cash only. 

There is little to see, but I still loved this place, the atmosphere was quite magical. Despite the obvious differences, it reminded me of Copan in Honduras and the Alto de los Indios Archaeological Park in Colombia. It started raining when I arrived, with thunder and lightning in the distance, so most visitors left (there were not too many people anyway), and I had the whole place to myself.