We went beginning of July this year and the water was swimmable but still cool and the bugs were still quite bad, but I suspect that had to do with the cold winter. I would probably go later in July next time around.
I cross dozens of times a year and have never had any problems, either way knock on wood. As you said Booze and pets papers. Also avoid guns going into Canada and bringing most perishable foods back to the US, the list of banned food going to the US is so long and complex we just avoid brining anything fresh/will spoil into the US all together for simplicity. Make sure you have passports and don't lie at the border and you will be fine.
