Patagonia is massive, beautiful and desolate. You can go extraordinary distances without seeing much, other than the occasional guanaco. As such you should always be prepared for whatever chance may throw at you. If driving, have spare blankets, food and water in case of break downs as the nearest mechanic may not be able to reach you in a day. If hitchhiking, have tents and appropriate gear in case you don't make it to the next town before nightfall. When in the backcountry be sure to follow all rules and guidelines to ensure that damage to the native environment is minimized as much as possible as there are many endangered species in the area. If you get in trouble help may not be able to reach you quickly, so prepared to take care of yourself!
Buses run constantly between Buenos Aires and Bariloche. They take around 24 hours but are very comfortable. Prices were running around 800 pesos but, as with anything in Argentina, prices are known to fluctuate wildly. Expect to pay around 100 USD. Buses are also availble all the way down to Rio Gallegos with stops along the way. This journey takes around 36 hours to complete
Flights from Buenos Aires to Rio Gallegos can save you the 36 hour bus ride if you're looking at heading down that far south. They sometime can be even cheaper than the buses, so it is definitely worth a look.
In Patagonia, there are plenty of unique and delicious things to eat. As in all of Argentina, beef is important, but particular to the area is the cordero, lamb, which is of a very unique flavor (supposedly because the Patagonian lamb eats a unique mixture of herbs found only in Patagonia) especially when grilled in the typical parrilla (grill).
Dulce de leche, similar to caramel and made by adding sugar to milk and cooking it, is used on nearly all desserts, including facturas (pastries eaten for breakfast or tea, or to accompany mate, filled with dulce de leche, dulce de membrillo, crema pastelera, roquefort, or many other things), alfajores (traditional cookies that consist of tiny biscuits stuck together), and many other Argentine desserts.
Mate (pronounced MAH-tay), a bitter tea, is drunk very frequently. Adding sugar is not rare because of its bitter taste. Many different things can be added to the drink, including milk, sugar, lemon or orange rinds, and cinammon sticks.