Day trip to Soave/Verona before scheduled meeting at 4:00 PM next day.

Parking in Soave is easy, just outside the walls or where your B&B suggests. Parking in Verona is not easy. There is a small train station outside Soave at which you might park.

You probably have less time than you think. If you have to be in your tour hotel at 1600 to meet the group, you probably want to be checked in by 1500 so you can freshen up and come down ready to go. Wherever you are in Venice and whether you take the bus to P Roma and then the vaporetto to near your hotel and walk, or if you take the Alilaguna from the airport and then either vaporetto or walk from the Alilaguna stop to your hotel you are talking about around an hour for the actual transportation and at least half an hour, probably more, to achieve the rental car place to the departure point, waiting for the scheduled departure, and organizing where you are in Venice. I'd call it 2 hours including the car return time and say you should be arriving at the airport by 1300. The drive is something just over an hour if no traffic problems so you need to be on the road by noon from Soave, earlier if Verona. That's a bit early for lunch so you should probably pack something.

Unsolicited advice here: you are wasting so much time getting and returning the car. Have you thought about using the train? There are easy buses from the airport to Venezia Mestre station on the mainland where you can join the rail network and whisk off to Verona for the day then back to Soave, then back to Venice, so easy and comfortable.

this is a duplicate post of the same question. That gets confusing. You have other answers in the other copy.

Hello Nigel, Thank you so much for the information. I didn't know there was a train station that stopped in Soave. We will forget about going to Verona and spend the day & night in Soave if we can manage w/o a car there. I will investigate the train. Again, thanks for the advise.
Rose

The name of the station is San.Bonifacio, it is served by frequent Regionale trains from both Venezia Mestre and the main station of Venice, Venezia Santa Lucia. Travel time is about 70 minutes to VE Santa Lucia. The other way it is about 15 minutes to Verona Porta Nuova.

San Bonifacio is just a few km to Soave, the station is at the far end of town.

Parking in Verona is really easy. Take the freeway from Soave to Verona (A4 direction Ovest - Milano).
Exit at Verona Sud.
follow directions to CENTRO (often marked by a target symbol)
Go straight all the way on Viale del Lavoro then becoming Corso Porta Nuova after Piazza Porta Nuova.
Just before the city gate, outside the city walls, turn right on via Paglieri. Right there there is a square called Piazza Cittadella. There is a big underground carpark.
I always park there. 2 min. walk from the Arena.