I have posted about the Sunset Bay Trail and The Simpson Reef Loop. There are actually a series of trails and loops that stretch from Sunset Bay up to Cape Arago, and then up and around to The Pack Trail. Starting from the beginning of the Sunset Bay Trail follow this around to the start of the Shore Acres Loop.
Cross the road and after a short walk to the left turn onto a trail start that will again merge you onto the Simpson Reef Loop. At your first opportunity veer right and follow the trail back to the Simpson Beach and continue to retrace your steps back to the very beginning. This whole loop of trails will be approximately 9-10 miles.