You can't miss with any of the three you mentioned. I think I would choose Treviso for what you describe. The walk is not long ant all from the station to the lovely center and the wondow shopping is great. And it's a very short ride.
Last month we spent 2 weeks in Venice with our one day trip to Conegliano but it would not be high on my list to repeat.
Got to say that this is an unimpressive link. No real detail. Not helpful.
Sorry, Tripadvisor can be so annoying and inefficient. My comment was referring to posting 3, from MonteCD