Hi Bhagya -
<<" on 9/23/2018 from Paris and leave on 9/27/2018 ">>
Good time of year. I always try to visit Switzerland in September, after the tourists ( mostly) leave, and before Winter makes its appearance, which , in some years, might make its initial forays into the higher altitudes during October.
I do like tohike, whichmakes some difference, but een without hiking, taking a cableway up from Wengen to Männlichen is rewarding. In 2009, on September 22nd, I took my daughter and then 8 year old granddaughter up to Männlichen and had a nice lunch, and walked from Männlichen to Kleine Scheidegg:
That is such an easy walk that it has the nickname "The Grannies' Walk."
Whetehr you take such a walk, or easier or harder ones, you have the pottentila for beatiful sights, as long as the weather cooperates and it is not cloudy and foggy.
Did you see this information about the Glacier Express? n It includes suggestions for doing part of the route....
It doe take a big chunk of tome, and also time to get to it and from it.
If you want to check out routes, including the good options suggested by Rockoyster, you will probaly find that, in addition to the time table, this map can be helpful. It is particularly good for travel, if you work on the menus and the under "Points of Interest." I use "Traffic" a lot, and, for some strange reason, hotels are under Gastronomy. Since some restaurants are also hotels, I check all the boxes.
Zoom in on the map to see the rail routes clearly, as I have done in this link: