Hi, Chani!
Padova: I have stayed at Hotel M14 near Prato delle Valle. Very clean, modern, will loan or rent you a bike, there's onsite parking if you have a car. Breakfast may be extra. A single non-refundable room in February is $56US. There's a tram/bus hub just a block or so away, the hotel is on a very quiet side street.
In Ferrara (spend 2 nights if you can), I like Hotel Corte Estense, I paid €70 with breakfast during high season. Again on a quiet side street around the corner from the cathedral and museum, a couple of blocks from Castello Estense. There is a great little restaurant on the main street in the same block as the hotel, they serve only regional foods. I'll try to find the name of it. Ferrara has more sights than you might expect. The Jewish museum is set to open (or reopen) in October. I missed it in July :-(
In Venice I like Locanda San Marcuolo. about 50 meters from the vaporetto stop. It's in a quiet area, has an elevator and includes breakfast. Tam Tam is a nearby restaurant in the Ghetto, serves wines from Israel. If you have time, go to Torcello for the mosaics in the ancient church. It's kind of a long walk from the vaporetto stop, but worth the walk. No bridges so it's easy on the knees.
Have a great trip, as usual!