We flew to Stavanger from Stockholm. As to Pulpit Rock, I saw many families and even people with dogs hike the entire trail. It was moderately strenuous, but definitely would recommend it as appropriate for a 12 year old. Just make sure you have appropriate footwear – saw a few tourists hiking in sneakers who had to turn back at the halfway point. The trail is pretty gentle for the first bit, but then the altitude gains really start to ramp up and the terrain turns much more rock and you’re scrambling over boulders for a bit. I would not consider it a complex or dangerous hike. It took us about 4 hours in total time (out and back).