Another well known spot accessible from the same bus is Gurtnellen. Take the bus to Gurtnellen Wiler, walk down through the village, past the church and across the river. Turn left alongside the railway line then pass under the line and climb along the otherside taking the lower of the 2 paths (5-10 min walk from bus-stop).
Here are a couple of examples of the view from here:
Looking towards Erstfeld: http://europeanrailwaysbybantam61668.fotopic.net/p66928954.html
Looking towards Goschenen: http://europeanrailwaysbybantam61668.fotopic.net/p66928949.html
I've haven't tried this location in Winter yet (planned very shortly) but have seen some so imagine it is accessible, Iwould imagine the light to be similar to that at Wassen.