Best drive from La Spezia / Cinque Terre to Venice

We didn't plan on stopping anywhere along the way

In that case, why not drop the car and just take the train?

Because the drive takes around 4 hours, and the train about 5.5 with 2 changes--dragging bags on and off 6 times.

From La Spezia take the A15 to Parma.
The A15 goes through the Apennines mountains (Cisa Pass) although largely through valleys and a tunnel under the pass, therefore you will see some mountains during that segment.
Once you go to the other side of the Apennines range on the A15 it's a flat valley all the way to Venice, and it's boring no matter which way you go.

When the A15 approaches Parma, you will take the A1 south (toward Bologna) for a bit, but around Modena you should take the A22 north toward Verona. Near Verona then you connect with the A4 (the Turin-Trieste freeway). Take the A4 East toward Verona. Stay on the A4 all the way to Venice.

For lunch I would just stick with the rest areas (Area di Servizio). They have restaurants in all of them and the Autogrill chain is good.

Warning: If you drive in March there is mandatory requirements to carry chains in most roads in Italy (from Nov to April 15), and certainly on the A15 through the Cisa Pass. Make sure you get it from the rental company, or buy chains at some Auto store.

Might be practical to weigh the baggage drills against picking up and dropping the car along with ease of where that happens.
Viamichelin, which I regard as slightly more accurate with drive time than google, says 4:25 to 4:48 drive time-no stops. I would build in at least one stop just because….The shorter time route is through Florence where traffic could be a concern.

I found train options of 4:18 and 4:21, La Spezia to Venezia Santa Lucia. Yes, 2 changes, so weighing in on baggage drills. If your bags aren’t huge and heavy, it’s quite easy to get them on and off as the train is usually level with the platform these days. We did this and we’re in our early 70’s and it was no big deal.

Although we enjoyed driving in other parts of Italy, even with two changes, the train would be option #1 for us. A plus is coming out of Santa Lucia right onto the Grand Canal. Wonderful. Remember, neither the driver nor the map reader
/ navigator gets to see as much or relax when driving.

We were going to drive for the shorter time and to see some different scenery. However, being from Florida y'all have me nervous about the tire chain thing!

Would that southern route through Bologna be warmer and not icy?

Gonna research the train a little deeper tomorrow for sure!

To go from the Cinque Terre to Venice you must to through the Apennines mountain range.

Whether you take the A15 to Parma through the Cisa Pass, or go all the way to Florence and then from Florence, go north to Bologna on the A1, you still have to cross the Apennines. That is the place where you might be caught in some snow, although not too likely in March, as the freeways in Italy don't climb too high in the mountains like in the US, but rather go through the mountains in tunnels. But the requirements to carry chains (or have winter tires), regardless of whether is snowing or not, is valid until April 15, as you can see in this freeway sign near La Spezia on the A15. The requirement is valid in all freeways north of Rome, although, as I said, in all likelihood it won't be snowing in March (but who knows?).

Since a car is not needed in Venice, it makes no sense not to take a train, unless this is an OP vehicle. With respect to route planning, viamichelin is superior to google maps.

Ya'll have convinced us to take the train to Venice. Too many unknowns with the weather and us Floridians freak out with snow and driving. :)

Good choice.

So now trenitalia.com is your next best friend. Easy to purchase tickets on line and have them on your phone. Takes a bit of getting used to using it. English is a choice, but you will still need to use the Italian station names in from/to.

There should be a train option with just one change at Milano Centrale. I know there is one from Monterosso. It goes up the coast through Genoa and then to Milan. Change there for a train to Venice Santa Lucia.

Lola is right, there are direct IC trains from Monterosso to Milano Centrale and high speed trains from Milano Centrale to Venezia S. Lucia, the station by the canals.

You need 15 minutes or more to transfer without stress at Milano Centrale.

To see the route via Milan on Trenitalia.com you must enter Monterosso as departure point. The site is programmed to show the faster routes, not to minimise the number of train transfers and the route via Milan is faster only departing from Monterosso.