There are some scenic rail journeys within reach.
You may plan to take one once you go to Luzern, because it is the obvious route. It is to ride through the Gotthard Pass
The timetable will route you under the pass. The scenery is on the old higher route, via Göschenen.
The second is a bit further away. Take the train via Domodossola to Brig, then take the "Lötschberger" train over the alps to Spiez via Kandersteg.
On both routes you can cut the return time by using the new routes via the new "basis tunnels."
The route through the Centovalli to Domodossola is a special rail journey from Locarno. Limited schedule.
While in Locarno, go up to the Madonna del Sasso.
You could take a lake boat ride on Lake Lugano.
The Customs Museum at Cantine di Gandria on the border , reached by boat or a difficult trail, is small but surprisingly interesting.
map.search.ch/.en.html ?pos=722308,95241&z=102 4
Also, the walk to Gandria from Lugano is pleasant, and the town of Gandria is fun.
The bus to Tirano from Lugano (The Palm Express) , then a ride over the Bernina Pass to Pontresina or St. Moritz is a possibility.
www.myswissalps.com/be rninaexpress/gettingth ere
The shortest connection from Lugano to Pontresina is just under 4 hours.
Above all, take advantage of the Italian cooking, while you are south of the Alps.