MC1--First of all, welcome and thanks for the kind comments about my book. Kudos for wanting to take a youngster fishing. It's a vital matter we all need to keep in mind (and do). With a four-year-old you won't get much fishing done, but do it anyway. There will be fun splashing around, throwing rocks (be sure to turn some over to look for insect life), and if you should by chance get to cast enough to hook a trout, let your understudy "help" net it. Anything which can convey excitement, fun, and action at this age is a real plus, and you can give a youngster no greater gift than an early and abiding love for fishing, hunting, and the good earth.
I'm enternally grateful to my father, who started taking me trout fishing when I was six, and goodness know how much he sacrificed. That's what you'll be doing, but in time it will all be worth it. ONe of the high points of my life was my daughter "lording" it over her husband when she out-fished him, big-time, on the Nantahala river a few years back.
Your post was a heartening one and I would love to see more of us giving thought (and time) to passing on a wonderful legacy.