La Chenalette is a really nice viewpoint located above the Grand St. Bernard Pass at 2800masl. At the top you have a splendid view of the surrounding mountains, including Mont Blanc and Grandes Jorasses as well as some "local heros" like Pointe de Drône, Mont Fourchon and Pain de Sucre. There is a nice mountain trail leading to it which is very well marked with stone cairns and red/white markings. The ascent with about 300m vertical ascent from the monastery takes about 30-45min depending on your individual speed. After a short ascent you do not hear any noise from the pass - it is amazing. Don't forget to look at the Saint Bernard dogs (look over the fence on the way back). If you are lucky you will see marmots and ibexes.
Until 1996 there used to be a ski lift which is now dismantled (Télésiège La Chenalette). In the spring and early summer be prepared to cross some snow fields on the way up. The cache is accessible in winter (as long as there are not more than 5 metres of snow) but you will need ski touring and avalanche rescue equipment. Be advised that the area is known for its avalanche activity with several deaths each season. Always remember this is high alpine terrain.
In the winter you can stay overnight at the monastery, in the summer also at the Auberge de l'Hospice.
Please hide the cache properly and close the lid very firm. The poor container has a miserable life up on the mountain.