In one part of our trip to Italy,from Venice we took the train to Lake Como via Milan,then to Cinque Terra via Genoa,then to Florence and continued to the South.
You can use the trenitalia website for the train timetables.

Start in Venice and fly home from MIlan:

Arrive VCE---3 nites
Train to Florence--get car---to Tuscany base---4 nites
Drive to La Spezia---drop car--train to CT base--2 nites
Train to Alba--stay at Villa Romantica--3 nites
Train to Como via Milan---see lake-3 nites
Private driver to MXP--last nite
Fly home from MXP

Personally, I would keep the car until Como, but I prefer having a car. If you have fewer nites you adjust the days.

Miscellaneous observations/comments:

I would want at least 15-20 days to cover your wish list.

If you put Lake Como and the Cinque Terre too late into October, you take a bit of a risk on the weather. It could be glorious all the way through October, but you just never know. Plus, in the second half of October, some hotels and restaurants in mid-Lake Como begin to close, the ferries go on winter schedules, etc.

So, I'd probably start this trip in late September and put Alba at or near the end. If you can't start in September, fly into Milan, see Lake Como first, then Alba, Cinque Terre, Tuscany and finish in Venice. Pick up the car in La Spezia after the CT and drop in Venice after Tuscany. The downside to finishing in Venice is that your outbound flight could be super-early.

But, if this were my trip, I'd drop either Lake Como or Cinque Terre because I think trying to put both near the front end of this trip creates logistical/travel problems.

You seem to have no interest in Florence. True?

Thanks all.
Jean - Yes, we don't plan on Florence only because I've spent 5 nights there in the past and my husband is not a museum afficionado, etc. We thought we would spend more time in Tuscany/Umbria area. Good point about the Lake Como or Cinque Terre. Which would you drop if you had to?

Personally, I liked Lake Como better than the CT. However, you specifically mentioned that you enjoy trekking, and that you are going in Oct when it is likely to be chilly and sleepy at the Lakes. So for your particular situation, I would recommend the CT over Como. (But it kills me to say this because I loved Lake Como!). Buon viaggio!

I also prefer Lake Como. If you head there in late September or early October, you don't have to worry about it being 'sleepy.' (And, IMO, sleepy isn't always a bad thing when you're spared enormous crowds.) As for weather, we've been to Lake Como from early October to as late as the last days of the month. It's never been what I would call 'chilly,' but one year it rained at the end of the month. A rain jacket or sweater were enough.

If you really mean 'trekking' or hiking as opposed to casual walking, there are many options around Lake Como. So many, that you may wish you had more time there or start thinking about re-visiting. Directly from Bellagio or Menaggio you can take longish hikes to one of the many mountain rifugios. You can even make a day-trip by train from Varenna into the mountains at Sondrio, Morbegno, Chiavenna, etc. You can hike from Varenna to castle ruins in the hills above the town. In some places, you can walk along the lakeshore promenade from one town to another. In the Cinque Terre, it's basically the trails between towns, trails which are very scenic but sometimes closed due to rock/land slides.

The food might be slightly better in the CT, but it's always felt more tacky-touristy to me than Lake Como. If you enjoy seeing gardens and visiting beautiful villas, there are some lovely opportunities on Lake Como.

Now I'll throw something into the mix that I just thought of. If you have any interest in pro cycling (Giro d'Italia, Tour de France, etc.), the Giro di Lombardia will be held in the Lake Como area on Sunday, October 6th. This is the last pro cycling event of the year and usually gets a good turnout of world-class cyclists, although rarely the top competitors of the TdeF and GdI. The route hasn't been announced yet, but it always, always includes a ride past the church of the Madonna del Ghisallo, the patroness of cyclists, which is located in the hills south of Bellagio. This church and the museum next door contain a large collection of cycling memorabilia, esp. related to Italian cyclists.

You are aweseome Jean. My husband would love to see the cyclist and I would never have known about this. So thanks. Thanks also to msteacher. I think we will choose Lake Como over CT.