Many people prefer to fly to Río Gallegos and then take the bus for the four to six hour ride to El Calafate. The busses are comfortable, and traveling this way gives you a very good view of the landscape - steppes and sheep, with an occasional guanaco or Patagonian hare thrown in for relief.
Either way you arrive, allow at least three to four days for the park. Weather conditions might not be optimal and you might need to wait for just the right photograph or glacier viewing.
El Calafate is geared for the visitor, with restaurants, markets, lodgings, tour agencies and the Ranger Headquarters for the park. Many visitors use the town as a base camp for Perito Moreno and side trips, then stay in El Chaltén for a day or two before traveling on.
Camping is available and inexpensive. There are campgrounds on Peninsula Magallanes. You'll need to take your equipment with you, but supplies are on hand. From the park, visitors can proceed further south into Patagonia to visit Ushuaia and Tierra del Fuego, go west into Chile to see Chilean Patagonia or go north. Chances are, if you are flying in or out of Argentina, you will be going through Buenos Aires.
Enjoy your trip to Parque Nacional Los Glaciares!