I've seen there's a panorama car on this train. How does one access it? Is there one in second class? Or would I need a first class ticket? (There's no mention of this route from RS.)
On what route? The route from Interlaken to Luzern by way way of the Brünig line (Golden Pass, a cog railroad dirctly out of Interlaken to the east) is scenic, but slow.
No, it's not on the Golden Pass. Basel is nowhere near Interlaken. Here's the exact info from the DB site:
Station/Stop Date Time Platform Products
Basel SBB We, 30.06.10 dep 07:03 4 IR 2163 Interregio
Number of bicycles conveyed limited, Please reserve, Snacks and beverages available, Observation coach
Olten dep 07:30 12
Luzern We, 30.06.10 arr 08:05 7
From Basel to Luzern is not a particularly scenic area, nice enough but nothing fantastic.
The train continues down the Vierwaldstaettersee (Lake Lucerne) on its way to Locarno through the Gottard pass. That's the scenic bit, one of the most scenic rides in the world.