8 days in northern Italy, first timer, suggestions on improving my itinerary

Whew. I'm tired just reading about that schedule. You're pretty much traveling to a different location every single day. That's a lot of time spent traveling and not actually seeing and enjoying a place. With only 7 1/2 days I would only pick 3 or 4 cities to see. If that's how you did your first trip to Europe and you enjoyed it, then go for it. As for me, I like a slower pace than that.

Wow. We are doing about that much in 3 weeks! And we don't do museums either. The thing we have learned about Italy is that the cities come alive at night. Keep that in mind. We stayed 1 week just in Rome and that was perfect.

Milan-Venice-Florence-Milan all by train.
Rent a car for a day in Florence to see some Tuscany. hilltowns.
That's all you'll have time for, as your itinerary would require 3 weeks.

You have an afternoon in Verona, a day in Venezia, 1.5 days in Firenze, 1.5 days in Tuscany (airport car rental is open on Sunday, I think), a day in Cinque Terre (you can drop the car Before Cinque Terre and take the train for the rest of the trip), a day in the Lakes (ferries and buses will get you around), then train to Milano.

Keep in mind that some hours will be taken up waiting for your car, for trains, and ferries. If that sounds good to you, go for it.

Are you flying into Malpensa and out of Linate, or in and out from Linate?
What time of year is this trip going to happen? Cinque Terre is not worth visiting in the cold weather months, and given your limited time, would probably be a waste anyway.

Given your time limitations, 3 nights in Venice, 3 nights in Florence, 2 nights in Milan with a day trip to Varenna on Lake Como. Or skip Varenna and spend an extra night in Florence and rent a car for a day of Tuscan sight seeing. More is not better, just packing up, unpacking, and glancing at the blur of scenery. Trains work great for this kind of trip. Cars are a burden, especially for cities.

I concur that your current plan is too aggressive. Based on your must see's and the time of year - I would narrow it down to Venice, Florence and some hill towns. And of course start planning your next trip to Italy inn the Spring or Fall when you can spend a few days in the CT. I will assume the CT is a must see because of the hiking and that is best during nicer weather. But if it is a deal breaker - swap hill towns for CT - and enjoy those lovely towns during shoulder season. Less crowds will make it much more enjoyable.

You don't need a tour to see David - but read The Agony and the Ecstasy before you go.

Don't think you will see anything at this pace of checking in / checking out.
If you travel to another area by car or train make sure you stay 2 or 3 nights per location, no 1 one night stays especially in Italy where there is often a distance between where you get off the train/park to your lodging.

Thanks to all that have responded so quickly.

I was worred I was doing too much.

Answers to questions:
Flying into and out of Milan's Linate airport via Dublin. I understand there is no train station at Linate airport, so I would need to find a way to the main train station in Milan (Centrale).

As far as CT, it was always high on my list, we leave in 1 week (Oct 11) so the plan is to be in CT (Oct 17-18). Will the weather, hiking, exploring be too cold in CT at that time? I know the weather just turned cold in SLC and I wouldn't want to be outside on a patio eating dinner. My wife doesn't like hot weather these days, so that is why we jumped on the trip thinking it would be cooler and less crowded too.

The suggestions on waiting on trains, getting to B&Bs with luggage in cities was very helpful.

Dave good to hear you are rethinking the plan. Most of us like you start with plans a bit too ambitious since there is so much to see and so little time.
I wouldn't want you to skip the Cinque Terre, I think it will be lovely then though could get rain.

We just returned from the Cinque Terre, stayed 3 nights in Manarola. Loved our stay and so glad we went.
Upon checkin and checkout though both my wife and I said thank goodness we stayed 3 nights, the hassles of getting here, moving luggage up through the town, etc... just would not have been worth staying only 2 nights. if I stayed one night I wouldn't have been happy at all.

You have enough days but might have to cut out some places. I would start by dropping Lake Como personally. Choose Verona or Venice, not both, etc...
Hill town in Tuscany or Florence ; don't think you have time for both plus CT and Venice.
Basically if you stick with 3 places plus Milan as you may need to sleep here your last night you can make anything work even though rushed it will be enjoyable as long as you plan ahead but when you start trying to fit in 4,5,6 places plus Milan it becomes the amazing race not a vacation.
Fly into Milan, train to Venice
Stay 2 nights Venice
2 nights in Cinque Terre
3 nights in Florence - spent one full day in Florence and take a day trip the other day to Siena, Lucca or San Gim.
1 night Milan
Not sure a car makes sense here
OR
2 nights Venice
3 nights in Cinque Terre
2 nights in a Tuscan Hill town
1 night Milan
Car probably only makes sense if the Tuscan hill town you choose is not well served by transit otherwise

Explore one lake (Como?). It's an easy one hour train ride from Milan. There are ferries for traveling between towns. I,suggest that you go to Firenze after landing. Spend four nights there. One day take a day trip by train to Venice; one day explore Firenze; one day rent a car and explore a couple of towns in Tuscany. Two nights in CT, then train to Varenna on Lake Como. Return by train to Milano and your return flight. I think staying in one place and exploring from there saves time moving from place to place and frees up time for vacationing.

From Linate there are several buses per hour to Milano Stazione Centrale, or you can take a taxi for less than €30, so that part's easy. The standard advice (which I agree with) is not to pre-book trains for your arrival day, since there can be delays. So, just buy your ticket from Milano Centrale to Venice Santa Lucia (or to Firenze Santa Maria Novella if you are starting in Florence instead) at the station.

I agree that the hard part is cutting this trip down so you will enjoy it. With only 8 days on the ground, you'll struggle to do even your four must-sees.

We based ourselves in Florence and took a day trip by train to Venice and the next day took a private tour from Florence to San Gimignano/winery/Siena. Florence is great as a base.