Logistics
The start of the trail is in Baños Morales, which is around marker 73km on the road into the Cajon del Maipo. The road is paved up to El Volcan, but the last 20km is not. The unpaved road is not great, but it is doable with a normal car. No 4WD necessary. There is also a bus service from Santiago, which goes once a day.
In Baños Morales there is plenty of parking and little stands to buy food/drinks/artesenia, and the entrance to the Monumento Natural El Morado.
El Morado
The CONAF-operated park charges CLP 2,000 (in 2015) to get in. There is one, very obvious, trail that leads via a small lake to the glacier El Morado. In summer, the glacier is not much to look at, but in winter it should be quite impressive. The total hike is 8km each way, and should take about 5 to 6 hours for the return trip. The first half hour is fairly steep, but the rest of the trail is practically flat.
The town is located at around 1800 meters above sea level, with the glacier around 2600 masl, meaning you climb around 800 meters.
WARNING: this trail has NO SHADE whatsoever and the sun is very strong in the area. Sunscreen, hat and water are indispensable. Shortly after the small lake (which is reached after 6km on the trail) there is a tap that provides the opportunity to refill a bottle or other container with water.
The cache
There was a, recently deactivated, cache at the end of the hike close to the glacier, but as a location that did not work particularly well (because of glacier run-off etc). So this cache is about 1km away from the glacier, in an area where the trail hugs the slope of the valley. It should be a bit better protected from the elements where it is right now.