The Ramparts is a walkway which follows the course of the River Boyne and the old Boyne canals (in places) Ultimately the intention is to have a walk/cycleway the whole way from Navan to Drogheda however this is a long way from fruition 
The existing sections are as follows;
1) A hardpack track starting in Navan and heading east towards Slane (there is an older series of caches along here)
2) A hardpack track starting in Slane and heading east towards Drogheda (there are 3 older caches along this section)
3) A grassy trail leading from Slane back west towards Navan (this series of caches is along this section)
If you park at the carpark coordinates at the Slane Bridge on the N2 you head towards the weir following the trail the whole way following the River Boyne. This is a completely flat walk along a grassy trail. When the series was placed (in the midst of a summer heatwave) the terrain was dry and easy but I cannot say what it will be like when the weather is less pleasant 
This is a linear walk so remember for every step you take you must return by the same route 
Between the old lockgate and this one there is a small makeshift stile to cross. The trail narrows briefly at this point.
The cache is placed near two makeshift seats along the trail and affords the finder super views of Slane Castle on the other side of the river. It is a micro container with log only so please byop. Please replace exactly as found in order to protect the cache from the many muggles. Assuming you are starting from the given carpark coordinates this should be your third cache in the series. As with all caches placed along our waterways caution should be exercised at all time especially with the geokids.
As to the cache name; my fiancee's son accompanied me on the walk to place the caches on condition he could name one of the caches. One of the highlights of last year for him was attending a certain concert at Slane Castle, across the river from this point, he thought the name was appropriate for this cache