Need help with 8 day Northern Italy itinerary which begins in Venice in late June.

Well the good news is that everything is relatively close and well connected. There is a high speed train that runs between Milan and Venice (buy tickets online in advance), and all the other places you've listed would be fine with regular trains.

Verona's sights can be seen in an afternoon if you're taking the train to or out of Venice. Padua is supposed to be a nice place to visit that is closer to Venice.

You can always come back - maybe a Genoa-> Milan -> Lake Como -> Switzerland trip a some point in the future?

edit: I found food is not particularly good in Venice, especially compared to the rest of Italy. If you trek out to one of the other nearby islands in the lagoon you can probably find wonderful seafood and risotto. Do your research ahead of time, eat later if you can (Italians eat super late... sometimes restaurants will cater to tourists during the early evening but cater to locals after 8 or 9pm) but keep lower expectations in general. Just enjoy the views :)

3 nights Venice.

Venice-Bologna. 2hours train.
2 nights Bologna.

Day trip. Bologna-Parma 1 hour 13 minutes train.

Bologna-Verona 1 hour 15 minutes train.

2 nights Verona.

Day trip to Peschiera del Garda. 15 minutes train.

Train Verona-Venice. 1hour 35 minutes train.

While 2 nights is a short time in each spot, your distances are not far so it should work. But to optimize your time, get an early start.

Trains would be easy with this itinerary:

Day 1-3 Venice
Day 4-5 Lake Como - Varenna
Day 6-7 Verona
Day 8 Fly out of Venice

Varenna is the town at Lake Como where we stayed with a RS tour. Bellagio is just a short boat ride away from there. You will love the Lake Como or Lake Maggoire area - very relaxing and beautiful!

I think you should only go to places that begin with a "V" (inserting smile here!). Verona is a fun city and very tourist-friendly. Their Roman arena has operas in June. Here's the schedule: https://www.arena.it/arena/en/pages/schedule-arena-di-verona.html
Even if you're not an opera person, it's exciting to attend an opera under the stars in Italy! On the other hand, if you despise opera, you might want to avoid Verona because it's popular during their opera season.

I've also taken a cooking class in Verona and an easy city bike tour - both through Veronality. There's also wine tours, etc. available. The Verona Card is an option to see a lot of their sites. You could easily take a day-trip to Vicenza, or Mantua, too.

I've been to Bologna & Parma. Parma does have my favorite European cathedral interior. But, I wouldn't put them on the short-list for a first time to Italy.

For the best food, step away from the main piazzas that carry tourist food and look for Italian menus. We follow our nose and/or look at TripAdvisor.

Como, Pisa, Lucia, Verona.

Wow! Thank you everyone!! Just need to decide between lakes! Verona will definitely be two nights! Jean, thanks for the heads up about the opera. La Traviata it is! So excited. And Rob, I love seafood and risotto, so will go to other islands! Gerri, appreciated the train times very much. Shows me we can do it. Will get started with timetables. As soon as I decide on the lake! Two nights per town it is...

So after going through the opera info, I started going through Rick Steve's calendar for June. Have already informed everyone we will be going back NEXT year in order to go to Spello for Le Infiorate! Have you all been? 9th Sunday after Easter - and if you go ahead of time, you can help with the flowers the day before! Will count my Sundays and get a reservation then.

Thank you again - it showed me that I didn't want a base for the entire time. Had read that Milan would be a good base, but I see that is not right for us - for this particular trip.

You all are much appreciated!

I did eleminate Varenna because of transit times both from Bologna 3+ hours and Verona 3 1/2 hrs and Venice 4-5 hrs.

Varenna is I think most easily done with an arrival in Milan, traveling onward from there, with a departure from another city.

I like the options that Geri presented as opposed to the Milan/Como trips. I would only make one change. Spend one night less in Verona, add it to Bologna and do a day trip to see the spectacular mosaics in Ravenna.