A head for heights is necessary to attain this cache, and an overnight stay would make it a more comfortable trip.
Access from Ben Bullen...use the Ben Bullen 1:25000 scale Topo map. You can drive for some distance 2wd, but the rest is 4wd territory to the Gap. We suggest you stop before the final hill to the junction at the hook in the track, and cut across to the cliffline, head north, (easy walking) and drop off the end, (not so easy!) cross the saddle and try the west side of the south end. The northeast end is tricky with a 4 metre vertical climb. The logbook is easy to find.
Prove your trip here by photographing the cairn, your team, and the view in one shot.
Enjoy the trip. You are looking at about 12k return.