4 nights in Switzerland

http://www.myswitzerland.com. Consider concentrating on the Bernese Oberland or Valais areas. Example: the area around Lauterbrunnen/Murren/Grindewald might be just the ticket you're after.

The"Lauterbrunnen/Murren/Grindewald" area is rather desesrted in early May. No longer enough snow for skiing but too much snow for hiking.

Places not to miss in Switzerland (google for them):
scenic train Chatelard - Emosson, may be combined with the visit of the Chamonix area,
Steam train Furka Pass (until first weekend of Oct)
Entirely walled medieval town of Murten
Roman theatre and museum of Avenches
Menhirs around Grandson
Gorges de l'Areuse and Creux du Van
Watch museums at La Chaux de Fonds and Le Locle
Underground mills of Le Locle
Musical box museums at L'Auberson, Ste-Croix and Seewen SO
Celtic lake dwelling museums at Neuchatel-Hauterive and Biel/Bienne
Caves of Vallorbe, Reclere, Beatus
Medieval city of Berne and it's fine museums
Ballenberg Eco museum and nearby Aar gorges
Lucerne: historic center, Rosengart Museum (Picassos), Glacier mills, steamboats plying the lake, cog railways to Pilatus and Rigi
Baroque churches/monasteries at Solothurn, St. Urban, Einsiedeln, St. Gallen
Subtropical gardens at Brissago Islands, Isola Bella (Italy), Isola Madre (I), Villa Carlotta (I)
Engadin Valley (St. Moritz - Scuol)
Bernina railway
Mustair Monastery
Swiss National Museum at Zurich with dependances at Schwyz, Prangins, Gandria, Wildegg
Aletsch Glacier (Riederalp)
Rhine falls and historic towns of Schaffhausen (with castle) and Stein am Rhein
Medieval Gruyeres with cheese diary and nearby chocolate factory (Cailler at Broc)
etc. etc.

That surely leaves a lot of possibilities. If small towns and villages attract, but traveling by train in Switzerland, you need to make some excursions. And heading back to Italy in a short time, you probaly won't go too far north. If coming from Milan, heading up to Zermatt and the Matterhorn from Brig and Visp seems a worthy idea. From there, via Visp you could head over to Martigny and go up to the St Bernard Pass or over to Mont Blanc and Chamonix. Then over to Montreux on Lake Geneva for Chillon Castle or to the Lavaux Vineyards at Vevey. Or take the Chocolate Train up to Gruyere, retrace your steps back to Italy, or take the Golden Pass through Interlaken to Meiringen, then take a PostBus tour over the Grimsel Pass and Nufenen to Lugano, or from Grindelwald to Andermatt, then train back down to Italy.