If you'll be spending all or most of your time in or along two cities, another possibility (though not specifically aimed at tourists) is the Point-to-Point card, which is a weekly/monthly/yearly pass for just a particular stretch between two cities. It also includes some travel on public transit in each of these cities; you'll need to find out the details for the cities you're considering.
My wife and I purchased these for the Bern-Fribourg route during a 15-day trip where we stayed in a city along the route. I think the price at the time averaged to about 15 CHF per person per day, and we avoided the hassle of buying train tickets; we could just hop on any train and go to Bern, Fribourg, or anywhere in between.