The cache can be approached from either direction, however on has to be on foot, the other can be driven to and parked by in the nearby car park at the visitor centre. Both are good experiences.
If you start the walk via Claggan you can stop in a convenience store for supplies and walk the whole route along River Nevis and continue past Ben Nevis taking in the views, of indeed the trail can lead you up the mountain itself.
If you approach by the road you can do on foot as there is a footpath, or on the road by vehicle. There are many things to see either way.
The cache itself you’ll find a small wooden footbridge. A ziplock bag with a pencil and airtight container inside, with waterproof paper log in that.
Hopefully the water isn’t too high the day you search.