In summer time (after the 21st of June) it is possible to get there on a ferry with the help of Veteran Fjordcruise AS . That's why before this time you can only drive. If you use GPS devices be aware of getting lost and alway control the way it shows you. It is better to print the road description from internet and insert the road sections step by step.
Trekking to Kjeragboltn Quite an interesting one - sometimes it is even simply a way vertically up. The way up and down lasts 5-6 hours (or even more if you stay for "drinking", "making pictures" and "having some rest"). In order to get to the Boltn you need to follow red letters "T" and sign post not far from your aim. When there is snow on the mountain it is a bit difficult to find the Boltn. After the signpost you need to go straight and after a slope you need to go to the right.
Most people start the hike to Kjeragbolten from the Oygardsstolen Cafe. There is a parking fee during the busy season. There is also a toll road on the way to to Kjerag, just before leaving Rogaland and entering Vest-Agder. This is 100 NOK at the moment. If you don't have an AutoPass chip, a photo will be taken of your plates, and you get a bill invoice per mail. The road to Lysebotn will usually close in October, and open in May (due to snow). This varies, so check with local road authorities.