No special access issues
🚗Driving takes roughly and hour from Helsinki and the easiest way by far is to take E75 to Mäntsälä center, from where you take the country road 1471 to the small village of Sulkava. From Sulkava you take the country road 1431 northbound until just before the small village of Nikinoja, you take the small road of Jerpinmäentie (note, this road is a loop, so when coming from the south, you'll pass the junction once). After about a kilometer, you will see the landowners dairy farm and behind that looms Rajakallio. Some 1.3km later you'll see a small road leading to a red barn. This small road has been often plowed free of snow, if that is the case, drive as close to the barn as possible and prepare a parking spot so you don't block the road. If there is not a lot of snow, simply drive next to the barn and park so that you don't block traffic on the forest road, or access to the barn or farming equipment.
🚶From the parking, follow the gps trail on the forest road to Aittakallio.