The cache is a small Lock-Box (450 ml). Initially it contained a logbook, a pen, an owl, a butterfly and a frog.
The cache is kept in place by a large piece of wood and covered with leaves. That's the way the hideout is supposed to look like. Please refrain from creating the typical unnatural array of sticks there.
Small hint: Start with the second sign from the right in the second row to find out what the riddle is about. This sign seems to be best known (C&R Offroad Team asked me if their assumption was right, so they got a hint as they were indeed on the right track).