The ideal itinerary for a three week "open-jaw" trip through southern South America Q My 22-year-old son and two student friends are going to South America in August for three weeks. They fly out to Rio de Janeiro, and back from Buenos Aires. They are thinking of bussing across Uruguay between the two cities. Would it be better to just book a flight? Kathleen Mulholland A Rio is one of the few "world cities," ranking with New York, Hong Kong and Sydney, and a great place to begin any exploration of South America. There is a lively backpacker community in the city, and they will be able to pick up all kinds of useful information - from great bars and restaurants to the latest scam (to which new arrivals are especially prone). Our most recent "48 hours in Rio" guide, available at ind.pn/48Rio, will help your son and his friends plan the first few days. Your son could fly from Rio to Buenos Aires, but this three-hour trip is disproportionately expensive (at least £200 one-way), and means he will miss a vast amount along the way. The standard means of long-distance transport in Latin America is the bus, which in Brazil is efficient, comfortable and reasonably priced. Since Brazil is the size of the continental US, your son and his friends should plan to cover more than a fraction of the nation on a first visit. They could explore the coast west of Rio, including a trip to the indulgent island of Ilha Grande. Once there it makes sense to continue south-west to São Paulo to appreciate its sheer scale, and to the fascinating city of Florianopolis - party and beach capital of southern Brazil. From here, it's a few hours south to Porto Alegre and beyond to the international border at the town of Chuy - gateway to a country that may prove a highlight. Uruguay - about three times the size of Wales - has superb beaches, friendly locals and a cheerful capital on a human scale (a rare thing in Latin America) in the shape of Montevideo. Inland lies endless cowboy country, while the architectural highlight is the beautiful town of Colonia on the River Plate. Buenos Aires is a mere hour by boat from here across the murky waters. Argentina's capital is handsome, sophisticated and vibrant, and the ideal location in which to spend three or four days at the end of a South American adventure.