Feb 7, 2013 - 2:48 AM
Hello Mrs. Luk, welcome to MySwissAlps,
Are you sure about your InterRail Pass? That pass is for European residents only. US citizens best look into the Eurail Passes. Pass types, prices, discounts, etc. can all be found here
All about the Swiss Half Fare Card, including a downloadable map with discount information, can be found here
. You need a card for everyone over 15 years old. Children up to and including 15 travel along for free.
Since you plan to drive, the Swiss Half Fare Card makes more sense than InterRail or Eurail. The latter two include free traveling but they're also more expensive, so they're economical if you do your long distance transfers by train.
Does this help?