Hmmm - our first trip to Venice we arrived by train sometime around lunch. It took a few hours to figure out the vaporetto, get to our B&B, check in, get settled, get back out and figure out how to get to where we wanted to go...we then decided to head for Murano (this was '08, so details/times are a bit fuzzy). We arrived to Murano about 3:30-4pm - well, most of the shops that day closed at 4:30-5pm - so I felt like we spent all that time to get there, then we had maybe an hour, then all the time to get back. Burano and Torcello would have not been possible.
I think spending time in Venice proper your arrival day is better - then the next day - if you still decide to do Mu/Bu/To - head out early - if you really want to see them 'properly' - you need a few hours at each spot (well, maybe not Torcello, but we spent a good 2 1/2 hrs on Burano first visit, 90 min or so the second time). I'd recommend getting up early and heading out as well - even if you go back to your room for breakfast after - nothing like seeing St Mark's Sq and stand on the bridge facing the Bridge of Sighs at 7 am when it is almost devoid of people - it's amazing - because by 10 am, SMS is packed, and you are fighting elbows and selfie sticks to get a photo of the B of Sighs.
Our first trip we arrived as stated above, then flew out the next evening, so we had about 36 hrs. Hindsight, we should have just wandered Venice itself and left the islands for another trip. Just seeing Venice itself is amazing.