If you are planning a trip to Cerro Tololo, you should be sure and read the Travel Information prepared by the Director's Office. Also, although it is a bit dated, there is some good advice in Bruce Balick's Airport Survival Guide.
You should read the CTIO Network Security Guidelines.
If you plan on bringing down your own computer, please read the CTIO Visitor Computer Guidelines.
Observer Support has prepared a helpful list of CDs and Videos available on the mountain for your enjoyment. Any donations to the collection will be gratefully accepted and acknowledged!
Be warned that La Serena is not one of the gastronomical capitals of the world, but if you get hungry, here's a rudimentary La Serena/Coquimbo Restaurant Guide.
If you intend to call your friends back home to tell them how your trip is going, you might want to first check the following document concerning the price of telephone calls.