Its still very warm there lizgregs, i'd ditch the boots and take some flip flops for use in the very unlikely event that you have to paddle!
Last minute eating tip (if its not too late). I'm home now but yesterday evening we found a nice restaurant in a lovely spot. Got the No1 vaporetto in the direction of Lido to Giardini (Gardens). Got off the boat and walked to the right along the bank. A few hundred yards along is a restaurant called something like Il Paradise. Lovely views, well made Spritz (with the BIGGEST olive ive ever seen), and a nice menu, not too expensive.
Recommended for lunch, or at dusk so you can still enjoy the views. If you go in the daytime the gardens looked nice and there's some sort of big exhibition going on there too, not sure what it was though!
whatever you choose to do, have a lovely time.