Welcome. I can relate to much of everything you said - from our ages, to having a family, to hiding and sneaking the booze, to being worried about social commitments with old friends who drink too much. It sounds like you are taking the right steps to begin on reclaiming your life - for yourself and your family. (Btw I also really like Rational Recovery and Easy Way to Quit Drinking as other sources of ideas, inspiration and work). It took me a long time to finally put the poison down for good - lots of suffering and pain, lies and deceit. But being on this side of sober for more than two years I can also tell you that there is truly a better life waiting for you. You have to do the work. You have to accept that the life you've lived in thrall to alcohol is gone for good and forever. But the peace, confidence, strength, power, calm, focus and everything else that come with sobriety continues to amaze me and sustain me on a daily basis.
And in re: the canoe trip. You'll get differing opinions here about how and when to talk to people about quitting and also about when to be around social events like that when you are newly sober. It sounds to me like you know what's best for you and your family - not going. For me personally just telling my boys that I couldn't go this year, making up any kind of excuse, is more than enough. The truth is that you are going to be more worried about what they are thinking than them caring much at all, at least that's my experience. Just make up some excuse - work, family, money, health and say you'll see them next year and that's that. Put it out of your mind and get down to the work that matters most - saving your own life.
Congrats on getting to the place you are at and finding SR. This places got me sober for good. Can do the same for you, just have to do the work.