Car Parking/Rental and Train for Liguria! Tips for Drivers?

I think you had it right the first time around--take a train upon landing and then pick up the car when you leave the area.
I would not want to drive more than an hour max after 14 hours in transit! Also, parking is a pain and the car will just be sitting.
Milan airport to the train station is quick. Look at the train schedules to make yourself more comfortable--if I was arriving at 6pm I would press on to the CT that evening.

However, to answer your question, we have stopped in Asti (by train) to break up a trip from Milan to Liguria, and it worked well.

If you arrive at MXP that late you can’t make it to Vernazza on the same day, or even to Genoa, or at least it’s very unlikely, because the last useful train departs from MXP at 19:43, which may or may not be doable depending on various circumstances.

I stand corrected--and surprised. Thanks Roberto!

Thanks everyone! That is what I thought as well unless renting a car. So, any recommendations of somewhere fun to crash that evening to spend the following morning before heading to Cinque Terre?

I would plan to sleep near Milano Centrale station, and depart the next morning.

I also wouldn’t attempt to drive so late in the night after a long flight. You are likely to be jet lagged too.

Train schedule from MXP to Milano Centrale below (make sure you don’t take the one to Cadorna. Trains to Genova and beyond depart from Centrale).
http://www.malpensaexpress.it/en/

Hi! I hope that someone who has actually done what you propose to do will answer you, instead of someone who is only planning to do a similar thing in a couple of months. (USA to Milan, train to Genova, then train to Camogli, then renting a car in Genova, then driving to Dolceaqua in western Liguria, then two weeks in Piemonte)

But, for what it's worth, I am offering advice as a person who has flown about 14 hours to Milan and then immediately taken a train to Venice, and another time a train to Parma. Not a big deal. HOWEVER, we arrived at Malpensa at 7:45 am, not 6:00pm, and I think that makes a big difference. Also, after a long flight to Italy, my husband has immediately rented a car for us and driven somewhere --- it is not much fun to drive so jet-lagged and probably not real safe, either. Plus, having rented a car in Italy eight times now, it does seem to always take way, way longer than renting a car in the US.

If I were you, I would take the express train into Milan, stay at a hotel you can walk to from the station (like the Hotel Berna about two blocks away), then the next day take the train to Genova (direct and takes about an hour and a half) and then a train to the Cinque Terre. Far less bother and stress.

Ha! Some people type faster and are less wordy than I am!

Thank you so much Nancy and everyone! I think we will do the express into Milan for that evening and stay at the Berna. Maybe even have a leisurely morning in Milan and aim to get to Vernazza in the later afternoon. I suppose I can do another chat for suggestions of 1-2 cool things to do in Milan in the morning (maybe visit the duomo and go to a cafe?), but open to suggestions here :)