My wife and I stayed here this October. It's quite hidden away but the best way to get to it from Marco Polo airport is by the Allaguna Blue line boat which brings you from there and get off at Fondamente Nuove. If you come in by bus to Venice you will need to find a vaporetto to bring you round to the same stop. When you walk off the boat immediately turn left and walk along the Quay towards the Hospital. When you reach a stone bridge cross over it and turn right and walk along the side of the canal. You are walking more or less South with the Hospital on your left. On your left you will see a large square with a church Basilica dei Santi Giovanni e Paolo, ( also large statue of rider on horse) turn left and walk past a restaurant and a cake shop to the top right hand corner of the square. Go through the passageway that leads you South again over a bridge on a canal. Continue until you reach the end of the passageway and turn right. You will follow this passageway for about 50 metres until you reach another square. Chiesa de Santa Maria Formosa. Walk straight across the square and through the gap between the buildings and turn immediately right. B&B Le Marie is immediately on your right. The Dimora Degale is next door and they hold the keys. This is about a 15 minute walk with your suitcases. Google Maps is quite good to show you directions.
The B&B Le Marie is up three flights of steep stairs and there is no lift so if you have mobility issues don't book it. The rooms are clean and ours had air conditioning. There was also a fridge and the bathroom had a large shower, toilet, bidet and wash basin. There is a breakfast area at the top of the stairs. Breakfast consisted of fruit juice, cereals, croissants and bread rolls with butter and jam. There is also tea or coffee. The staff were very helpful and friendly. We would definitely stay there again. St Marks Square is about 10 minutes walk away once you get your bearings around the maze of narrow passageways.