Patricia, lots to see and do, both in Venice, and nearby.
Yes, you can visit Murano, Burano and Torcello on one full day by vaporetto, as long as you do not get too absorbed in the glass on Murano. In the main commercial area of Murano, some of the larger shops have “private” galleries upstairs or in back, with really beautiful large pieces priced at hundreds and thousands of euros. Worth seeing some of these, Maybe they just invite people with no kids in tow, or whoever they think are high spenders, but you can always ask to visit those. In the regular shops with smaller items, if buying, make sure things are marked “Made in Murano”, otherwise they may be made in China. Beyond the commercial area, you can keep walking and find a much nicer part of Murano, by and past the Glass Museum, and out to San Donato Church. I found a nice glass makers co-op shop with some very nice things at very reasonable prices.
Burano is wonderful for just strolling around its residential neighborhoods, taking photos and eating a seafood meal. If you like lace, there is a Lace Museum, and you can find some pieces of old or handmade lace at high prices. Low prices usually mean machine-made, often in China.
Torcello is a very short vaporetto ride from Burano, like 5 minutes. Then you walk about 10 minutes, to the church complex where Venice was born, hundreds of years ago. There is a combined ticket to see the three buildings, so give that about an hour.
Easy day trips by train are Padua, Vicenza and Verona, about 30, 60 and 90 minutes from Venice. You could easily spend a whole day or more in Padua or Verona, not sure how much time you would need to see key spots in Vicenza, I haven’t been yet. I think trying to visit two on the same day would yield a very surface visit, without enough time to explore the most worthwhile sites. Since transit time is so much less for Padua, I would focus on a visit there, Scrovegni Chapel which requires advance ticket, a beautiful food market both inside and outside, and the Basilica of St. Antonio.
enjoy!