Patagonia's dramatic and breathtaking natural landscape offers the family plenty of oportunities for adventure and enjoyment. Torre del Paine is must visit place if you go as far as Punta Arenas. It is a five-hour drive south but the views will dazzle adults and kids. You can also take a bus from Punta Arenas to the bus station in Torres del Paine town, make arrangements to have your hotel pick you up. If you drive, be sure to rent a 4x4 as the last two hours you'll drive on an unpaved road. 

In the park, the family will certainly enjoy all the activities offered. You can rock climb, fly fish, navigate in the lakes, hiking along the mountain trails, walk on the ice, try some kayaking along the mountain creeks or enjoy the park on horseback. You can tour the park by car, keep in mind that the roads are not well maintained so the ride will be under 15/20 mph.  

For further details, check the park's website at http://www.torresdelpaine.com and find the tour operators that best suits your needs.