My wife and I have decided to make the trip from Genova to Stuttgart by train rather than fly. We know; it'll be a long day, but we don't mind being on the train after being "on the go" for the week preceding this leg of the visit. We will be using a Select Pass which we purchased from RS. Will/should we get a reservation on the Milan-Zurich leg of the trip, and for that matter on the Zurich-Bern and Bern Stuttgart legs? We're not familiar with how busy these trains are in late September. The Milan-Zurich leg occurs mid-day and the Zurich-Bern-Stuttgart legs are in the afternoon and evening. If reservations are recommended, can they be made in the Genova station or should we go on line to make the reservation(s). We've never made a reservations using a pre-purchased Select Pass; we know the Select Pass carries with it "first class" seating, but not actual seating reservations.
Depends on the trains. Looking at the schedule, there is an IC train leaving Genoa PP at 9:19 and 12:19 requiring a reservation (3 euro per person), connecting to an EC in Milan that also shows compulsory reservation. My gut feel is you can get the reservation at the station in Genoa. Depends if it is a busy holiday weekend or a week day. It is very unlikely the trains would be full, especially in 1st class.
You will not go through Bern unless you specify a stop over there. The EC train goes to Zurich via the Gotthard Tunnel. The EC train to Stuttgart goes through Schaffhausen.