I've been thinking about your dilemma and remembering when I was held hostage to AH whims regarding visitation. It's not a fun place to be. Eventually, I learned to adapt to "the uncertainty" of coparenting with and alcoholic.
So, here's some practical advice. Plan your camping trip, just don't plan a definite date. He is an active alcoholic--he will flake out on visitation. I can almost guarantee it. But, he won't give you notice.
What I would do is get all the camping gear together in a convenient place so it can be tossed in the car on short notice. Make sure everything is ready to go--fresh batteries in the flashlights, etc. Make a list of everything you need to take and put it in the pile. Make a grocery list for a weekend camping trip and keep it handy. Pick a place to go not too far away, and pick an alternate near the first place in case the campground is full.
Then, when he calls at the last minute to cancel his weekend visitation, not only do you get your camping trip, but you will be the hero parent who saves the weekend when your little one is disappointed in his dad.
That's just what I would do,
L