RE: How old should the little guy be?
Even today, with my son 12, we'll start out scouting, do some fishing, switch to bow fishing, back to scouting - keep moving and changing it up.
Turkey hunting is pretty pro-active and exciting for younger ones; keeps 'em moving and intrested.
Started my boy very young scouting, taking pictures, looking at sign, bugs and what ever was interesting. Found a deer skeleton from winter kill and talked about that for an hour once.