Take the turning to Pitlochry (it is signposted but small sign easily missed - there's a P 450yds warning sign just before the actual junction). The road bends to the right, then turn right into Fonab Business Park almost immediately. This is a no through road but has a large turning circle at the end, so is suitable for caravans / campervans and you can just park at the side of the road. Note if the nearby theatre has a performance on this may be very busy with overflow parking.
You can easily walk down to the fish ladder at the dam from here plus other local attractions where you can have a drink or cup of coffee before you hit the road again. There is a footbridge (nice and shoogly!) which you can take from the hamlet of Port Na Craig over the River Tummel to give access to the town of Pitlochry itself. A plaque on the bridge states that it was "erected in memory of Lt. Col. George Glas Sandeman of Fonab, opened by the Marchioness of Tullibardine, on Empire Day 1913". Another plate notes that it was manufactured by the Lanarkshire Steel Co Ltd, using the Siemens Martin Process. It has recently undergone renovation & repainting, reopening April 14
This area also has numerous marked paths & walks.
You are looking for a small lock N lock box in a cammo bag.
Cache box has some swaps and room for small trackables or coins. Note the 'bean' pen is not a swap and stays with the cache.