If you can pay for the privilege you can hire a helicopter flight, to get to either Termas or Garganta del Diablo shelter.
From Santiago, it takes less than 2 hours to get there, at a cost that ranges from US$ 1400 to up to US$ 7000, depending on the type of aircraft you choose.
The cheapest are Bell 206's, which can take 4 passengers, but bigger Iroquois go for US$ 5000 and carry 9 passengers.
You pay for the whole helicopter flight, NOT per person. Fares are one-way.
Alfa Helicópteros is one of the best helicopter companies in Chile, and have pilots specialized in mountain operations.
Also, Heliski is a good, new one, specialized in carrying skiers to virgin snow mountain tops (www.heliski.cl)
From SANTIAGO, Buses Nilahue has a very comfortable daily service at 0825 from the Terminal Sur to Las Trancas only. Trip is US$ 8 and takes 6 hours. It returns from Las Trancas at 1600.
From CONCEPCION, Buses Linea Azul goes at 0600 and 1100 directly to the Termas (ski lift) for US$ 4,50 (3 hours).
From CHILLÁN, passing Linea Azul, Nilahue and a local company buses go to the hotel (except Nilahue) at 0800, 1000 and 1230, and several times in the afternoon. Trip takes 2 hours and cost US$ 1,50.
The last returning bus is at 1800, bound for Concepcion.
When wallking in the ski tracks, be very careful of the many high-speed ballistic objects that come down the slopes: skiers and snowboarders.
These usually go downhill at a very high speed, and assuming that there's nobody on their way; so, when walking there, keep to the inner side of the slope, as the skiers take wide turns.
Be careful when there's fog (can be very thick), wear brightly colored clothes, and ideally take a whistle to signal your presence.
Snowmobiles sometimes climb and descend by the tracks too (the medical snowcat is quite a threat if you're not paying attention)
Luggage and bags:
If going to Garganta del Diablo: internal frame pack, and a small daypack for venturing around the shelter.
NOTE: essential items are highlighted in RED
Clothing/Shoes/Weather Gear: In winter: Gore-Tex (or similar) pants, parka and gloves. Plastic mountaineering boots or GoreTex-lined hiking boots.
Gaiters, balaclava, fleece jacket, spare gloves, pants and socks, glacier-type sunglasses.
In summer: fleece jacket, long trousers, standard hiking boots, hat, balaclava, gloves, T-shirts
Toiletries and Medical Supplies: High-factor sunblock, some descongestive pills (for possible colds).
Altitude is not a problem here.
Photo Equipment: Mechanical camera (it gets quite cold), wide angle lens, polarizing filter, spare batteries, cable release (for long-time exposures in twilights)
Camping/Beach/Outdoor Gear: If camping, an expedition-type tent (TNF: Mountain-25, VE-25, or MH Trango 2 or Annapurna) is essential, as winds are extremely strong and easily rip and blow away weaker tents.
A good sleeping mat, warm sleeping bag, headlamp, camping stove, footprint for tent, GPS receiver (if climbing around)
Miscellaneous: In winter: crampons, snowshoes, skipoles, ice axe (if climbing the volcanoes), 2-way radios, extra fuel for melting snow
The main activities around the hotel area are skiing and snowboarding; there are 8 tracks of different level of difficulty, but all af them have a beautiful scenery, and some of them go across bushes and even get close to the Chillan twin volcanoes.
The lift rates are: US$ 30 (adults), US$ 20 (children up to 12), and US$ 23 (Women's Day -Wednesday- and half day -after 2 PM).
Lifts begin to operate at 900 AM, and close by 500 PM, although tracks can be used until anybody wants (note that in winter, it gets dark by 530 PM).
Equipment: If skiing/snowboarding, take the gear you think you're going to need.
In spite of this, gear can be rented in Las Trancas or around the hotel itself; they have everything for rental , from gloves to skis and snowboards. A credit card or a blank check and a suitable ID are necessary for renting.
In Las Trancas there are also several ski shops selling brand-new gear at average prices.