Assuming no delay for the flight and getting a rental car, the earliest you can get to preikstolen is around 5-6pm. Hiking to pulpit rock is still possible since sunset is around 10-11 pm in the summer, but that makes an extremely long first day. If you stay in stavenger for the night, I recommend take the ferry from lauvvik to lysebolton. This save you time and energy, the alternative is a 3 hour drive. The kjeragbolten hike is about 7 miles and takes about 5-6 hour. To make the trolltunga hike the next day, you then have to drive 5 hours to Odda afterward.