Very nice and easy family-friendly hike to a hidden gem in the Ryfylkeheiane - Kvanndalen. You'll get to a cabin by the Stavanger Trekking Association where you can spend the night. Or simply hike back (total length there and back is 8km).
If you climb the hill just north of the cabin, you'll be rewarded with a splendid sight over the valley.
Parking at Kvanndalsdammen - free and readily accessible over a gravel road - no toll.