>>447773My son and I go in winter(pic), he's 6, the trick is to keep him busy, scavenger hunts you set up the night before, story books, flora identification, hunting, tracking, ice fishing, setting and checking snare traps, etc. It also helps to give them thier own equipment, their own bb gun, fishing rig, etc.
Going outdoors is a release for us adults who like to get away from the stress and bustle, kids aren't stressed, they don't need an escape, what they do crave is hands-on education and almost constant stimulation.
4 might be too young, I have a 3 year old daughter as well, I wouldn't take her out overnight in the winter for an /out/ style excursion, she wouldn't like it very much yet.