From Stavanger, take the ferry to Tau (45 minutes). From Tau, there are 20 km to Preiketolen Parking and approx. 25km to Forsand which lies at the mouth of the Lysefjord. The parking area has toilet facilities, information and food service. You wil also find the Preikestolen Fjellstue here. There are no toilets along the trail.
You can also drive the E39 to Sandnes, then follow the road Rv. 13 to Lauvvik. Take the tourist ferry from Lauvvik to Lysebotn or the ferry from Lauvvik to Oanes (10 min). From Oanes it's about 15 km to Preikestolen Parking.
Get the tourist ferry from Lauvvik to Lysebotn or drive from Stavanger via E39 to Gjestdal, Hunnedalen, Sirdalen, and then drive over the famous Lysebotn road to the mountain restaurant Øygardstøl where the hike starts (140 km)