There is a link track bewteen the Dress Circle Track and the Takapu Road entrance (which forms a loop with the Takapu Ridge & Cannons Head route). Along the way there are great views overlooking Porirua, its harbour and sea beyond. It's also a great place to see the formation of the new motorway below including the viaduct over the Cannons Creek Gorge.
Like most of the Regional Park, great caches hides are hard to come by so this is kind of forced to fit the location.
Note that many maps show this track descending down to duck creek and joining the service road. This was the case prior to the motorway construction but the loop now stays up in the hills as shown above.
There are several waypoints in the listing marking the alternative path that you have to take until the motorway underpass is available (or if you're heading down to the other caches). The trailheads are where the junctions are at each end and some select waypoints in between for reassurance. There are orange markers on this track but some of them are missing or in places hard to see from the previous marker. The descriptions are for heading down to Takapu Road because I always come down this track from Cannons Head.