Pavia/Certosa instead of Verona?

I have been having second thoughts on day tripping from Milan to Verona. A train ride of 1.5-2 hours, plus a bus ride to the city centre, means that travel time could be well over 2 hours each way, or around 5 hours in total!

If not Verona, then where (considering that I have already planned day trips to Lake Como and Bergamo)?

Seems that Pavia and the Certosa could be a good choice.

"At one time, the quiet and remarkably well-preserved little city of Pavia, 35km (22 miles) south of Milan, was more powerful than Milan. It was the Viscontis who built the city's imposing Castello, made Pavia one of Europe's great centers of learning (when they founded the university) in 1361, began construction on the Duomo (with the third-largest dome in Italy) in 1488, and founded the city's most important monument and the one that brings most visitors to Pavia, the Certosa.

The Certosa is 8km (5 miles) north of Pavia. One of the most unusual buildings in Lombardy, if not in Italy, this religious compound was commissioned by Gian Galeazzo Visconti in 1396 as a Carthusian monastery and a burial chapel for his family.

Admission to the Certosa is free; it's open Tuesday to Sunday 9am to 12:15pm and 2:30 to 6pm.

Half-hourly trains from Milan usually stop at the station near the Certosa, just before the main Pavia station (30 min.). To reach the Certosa from Pavia, take one of the half-hourly buses from the Autocorriere station (next to the train station); the trip takes about 15 minutes."

From Trenitalia timetables, fast trains leaving from Milan's Central Station usually go straight to Pavia (23 minutes) first, before connecting to Certosa (referred to as Certosa di Pavia). Other Milan stations have faster and more direct trains to Certosa.

Possible itinerary: Milan Central Station - Pavia - Certosa - Milan city centre.