Hi, after read Rick Steves' book, it looks like I don't have to make reservation on all scenic trains (I bought the Swiss Pass), is this right? Which routes are required for reservation with a Swiss Pass? Which routes are optional? Do you think the standard trains are just fine? I like the standard trains time flexibility. Your advices are appreciated. Thanks!
You don't have to make reservations on any trains in Switzerland, and in most cases it is not possible unless you are a group. For the scenic trains you only need a reservation if you want to travel in the special scenic (large window) carriages. On some (the glacier express for example) you can get a meal at your seat, which you also have to reserve and pay for.
based on your other post you got your pass from Rail Europe, they would be glad to explain your options and sell you a reservation. Or as in my case, they might tell you that depending on the time of year you don't need one. You can also buy a reservation directly. On the Golden Pass for November RE told me not to bother, and they were right they were plenty of seats, although I saw several seats marked with little RESERVED doilies.