Should we park our car at the airport then do we stay on mainland one night and take the train into Venice OR can we drive as close to canals and leave our car at a car parking area in Venice??
I lived in Venice.
Please park your car in Mestre in front of the train station.
The park in Venice it costs 3 times more.
U can get Hotel in Venice if u want something special and expensive.
U can get hotel in Mestre near the train station and get the train (1 every 10 minutes) to Venice for cheap price.
I stayed at a hotel across from the station in Mestre and took the train in every day. I had a very good room for much less than a room in Venice proper would have cost. The train runs frequently and is definitely no hassle. Most guidebooks recommend leaving the car elsewhere than Venice.
I would suggest parking at the garage right by the water taxis that take you into Venice. It is a little pricey, but you're right there and that way you have the freedom of having your car if you need to leave etc. Going to Venice by by boat is beautiful and it's worth it. Also if you will be there a few days, definitely by the water taxi pass - you can buy them for 24 hours/ 48/ 72 etc. which makes it cheaper to ride around since that is the only real form of transportation once you are in Venice.
You can get parking quite easily in Venice, there is a big multi-storey car park near the railway station but it is very expensive. You could pay €30-€40 per day. If this is your first time in Venice then it is also really nice to arrive by boat. I recommend you park at the airport and take a water bus straight up the lagoon. You need to walk to the docks area (about 7 minutes) where you will pick up a vaporetto.