Round trip up Astridnatten. First half part up to the top is on a marked trail. Decent goes on a older trail slightly overgrown but a fine and dandy gradient down Kvigedalen.
Parts between the top & the lake of Luretjønn, and the passage north of Heimstaulmyri are on very small to basically no trail at all (see route marking below).
Red dots from the starting point at Veslestaul to the top of Astridnatten. Slightly faint red marks the last kilometer towards the top. No marking from Astridnatten back down trough Kvirkedalen but a ok trail thats easy to follow after you get to the little lake of Luretjønn.
Shortly after you passed the small cottage/cabin the trail makes a turn to the south (left) here you have to continue westwards, north of the Heimstaulmyri wetlands, on a small trail (need some good eyes to see the trail but its there). It connects to the gravel ATV track that takes you back to the parking at Veslestaul.