Where to stay in Venice arriving by car

If you just absolutely must take your own car then park it in the big parking garages at Tronchetto which is actually on Venice Island. Do not stay outside the city in the industrial mainland Mestre.

We're taking our car because we'll be on a road trip through Slovenia and are returning home through Italy. I'm worried about whether there will be room at the big parking in Venice. Perhaps it makes more sense to park in Mestre (I see there is a parking garage across from the train station) and then taking the train into Venice and spending 2 nights at a hotel there.

IMO, if you have to stay in Mestre there is little point in going to Venice at all. The only reason to go to Venice is to be there in the evening and soak up the atmosphere. If you day trip in from Mestre, you will be seeing the same Venice that 10,000 bus tourists and cruise ship passengers will see.

I would second the recommendation to park at Tronchetto, take a vaporetto to a hotel in your favourite district, and really enjoy the city. Check out Pensione Guerrato, on a quiet lane near Rialto.

No, what I was proposing there was to park in Mestre and then take a train and stay 2 nights at a hotel in Venice, just going back for the car at the end of the Venice trip. I was wondering if anyone else has done that--left a car somewhere outside of Venice.

I agree with the posters that you should park at the Tronchetto. That puts you at the Piazzle Roma and vaporetto. We stayed here:
www.hotelarlecchino.com

There are also a couple of parking facilities near the Venezia Mestre station. Since prices might be lower than Tronchetto or Piazzale Roma, I recommend checking that option too. Once parked you can take the 10 min train ride to Venezia Santa Lucia station, the main station in the historical center of the city (Mestre is still part of the city of Venice, but it’s the newer part in the mainland.

I've read that speed limits are strictly enforced on the causeway from Mestre into Venice. If you do drive in, make very sure you stay under the limit.

Tronchetto Parking: https://europeforvisitors.com/venice/articles/tronchetto_parking_garage.htm

Thanks for all the good advice! We'll decide as the time nears which parking lot to reserve. I'm putting off making reservations until we see what the situation is for travelling in Italy this summer.