I started taking my twin boys on drive in cabin based fishing trips in Canada when they were 2 years old. I did this every year until recently. They are now 23 and fishing fanatics. At about age 15 we took them on a one week canoe-camping-fishing trip. They were not too fond of the work involved, setting up camp, paddling everywhere, limited range restricting fishing opportunities. They have been with me on 3 recent Quetico trips. They still enjoy the fishing aspect the most, but now handle the canoe-camping much better than as teen agers.

I think if I would have started taking them canoe trips from about age 5 or so, gradually increasing their exposure as you suggest, I suspect they would now enjoy the canoe-camping aspect more than the do.