The main sight is Aconcagua itself, which is visible from RN 7, but there are better views from Laguna Horcones, about two kilometers north of the highway and about 20 minutes from the ranger station (though probably a bit farther than the 400 meters the trail sign suggests).
For day-hikers, the best outing is Confluencia, about eight kilometers from the ranger station, at an elevation of 3,368 meters. For a three-day camping trip, the best option is to Plaza Francia, another 13 kilometers to the north, at an elevation of 4,500 meters. This is the base camp for the highly difficult and technical Pared Sur (South Face), first ascended by a French group in 1954.
Most climbers take the longer but technically simpler Ruta Noroeste (Northwest Route) to Plaza de Mulas, 4,230 meters above sea level, where there is camping and even a hotel, and then try for the summit. Hikers can go as far as Plaza de Mulas, for which it makes sense to have a seven-day permit.
An alternative approach, longer than the Ruta Noroeste but less technical than the Pared Sur, is the Ruta Glaciar de los Polacos (Polish Glacier route), pioneered by Polish nationals in 1934. Starting at Punta de Vacas, 15 kilometers southeast of Puente del Inka , this route is less crowded than the others but more time-consuming and expensive.
Note that there are variations on all these routes. By whatever route, Aconcagua is a serious mountain that requires excellent physical conditioning, time to adapt to the great altitude, and proper gear for snow, ice, wet, and cold. People have done the summit in as little as seven days from Puente del Inka, but at least an additional week is desirable.
Seasoned mountaineers can and have climbed Aconcagua  with only their backpacks and boots for support, but less-experienced travelers with the yen (or dollars or pesos) to stand atop the Roof of the Americas usually contract overseas package tours or make logistical support arrangements with local guides and muleteers. Most local operators are based at Penitentes  in summer, but also have offices in Mendoza  proper or nearby suburbs like Godoy Cruz or Guaymallén. Aconcagua Express, however, has its main office in Santiago, Chile.
All of the following operators have substantial experience on the mountain and either have or can arrange pack mules. For suggestions on overseas operators, who usually subcontract with one of those listed here.
Augusto Mira Fernández 14248, Las Condes, Santiago, Chile
Barcala 484, Mendoza
Olascoaga 2273, Mendoza
Vicente Gil 471, Mendoza
25 de Mayo 2985, Villa Nueva, Guaymallén, Mendoza
tel./fax 0261/428-3157, cell 0261/15-500-7718
tel. 800/516-6962 in the U.S.
Juan B. Justo 345, Mendoza
Perú 1499, Mendoza
tel. 420-4811, cell 0261/15-509-4147