four days after Tuscany

Are you spending any time in Florence? Venice & Florence are 2 of our favorite European cities. We also LOVE Sorrento, but I imagine you want to travel North, not South.

After Bologna, you could stay in Verona. It's close to Vicenza, so you could maximize your first day at Vicenza.

hi why don't stop in Ravenna or Ferrara after leaving Bologna? Those are worth visiting: Ravenna with its mosaics and basilicas dating back to the time when Ravenna became the Roman Western Empire ' s capital and Ferrara as Estensi family ' s renaissance Town. These could be done in a day trip when heading to Veneto region.

...but I also agree with Jean: Verona town of Romeo and Juliette would be great for a honeymoon!

To be so close to Ravenna and miss it would be unfortunate. The place is lovely and mosaics breath taking. I think they have luggage storage next to the station. From Bologna you would take a regionale train, just under an hour. Spend the day. Leaving From Ravenna you could take a regional train to Padua via Ferrara I think. Or go back to Bologna for a high speed train to Verona.
Ravenna is small, well cared for, friendly people. The town is level and a pleasure to walk in. The mosaics are in the basilica’s which are walkable one to the other with one exception. There is one a short ride outside of town accessible by bus . I am returning to Ravenna this fall, first trip was a day trip from Florence. Staying 3 days this time. Would encourage you to go.

Bologna isn't a bad place for 4 days - it's a rail hub, so you can day trip without changing hotels. Ferrara, Modena, Padua are easy day trips. Even Ravenna can be a day trip, though it's a little longer train ride.

I haven't been to Lake Garda, but maybe you want to experience lake country? You didn't give the month of the year, which affects crowding and availability, as well as heat. I have stayed in Reggio Emilia, which has much less to do than Bologna, but is attractive, and has a weekly market. We actually went back to Florence from Reggio to take a one-weekday-only tour we learned about while in Florence. The train was easy.

I'm not urging you to read (apparently, reverently approached in Italy) "The Betrothed", which was recommended in the paper by some intellectual celebrity - it took me months ... but it's about northern Italy in medieval times, and covers several specific places.