This is good stuff. Something like Hotel Olimpia or Hotel Moresco sounds perfect. We'll be coming via private shuttle so driver could likely get us as close to the closest bridge we'd need to walk over. 2-4 minute walk to hotel, dump luggage, sightsee, back to hotel at night, up in the morning, walk 4 minutes, taxi to airport. For 1 night, seems like it would be a lot of work to get to/from St. Marks with luggage.