This is a fun downhill trail from Vestbyveien down to Skiphelle beach. It starts at a gravel road going south marked "Røyspytten" and is clearly marked with light blue paint strips on trees and rocks, as well as signs at the intersections towards Skiphelle.
Once you start going up the gravel road, keep left at the first fork. Then just as the road seems to become someone's backyard, keep straight, and you'll see a small bridge as the trail continues through some trees along a field.
At the fork at the end of the field, make a right towards "Skiphelle" and start your descent. While there are flats and even small uphill parts, most of the trail is a pretty easy descent. There are a rocky sections where you'll want to watch your footing.
When the trail spits you out at the bottom, you are just across the road from Drøbaks biggest beach.