Lucerne is the Swiss city that looks most like the postcard: a covered wooden bridge, a preserved old town and a lake ringed by peaks you can reach by boat and cogwheel train. It is an easy day trip from Zurich and a better overnight if you want the lake without rushing.
Most tours combine the old town with a lake cruise or a mountain — Pilatus, Rigi or Stanserhorn — and run year-round, with the boat-and-rail combinations at their best from spring to autumn.