Always ask permission before going on someone’s land. Respect “No Trespassing” signs.
Unless you’re asking a neighbor you know because you want to stay close to home during a walk, there really is no need to hike private property. Public trails abound.
Great public places to day hike with kids include:
g Gem and fossil trails
g BLM land
g National Natural Landmarks
g Wildlife sanctuaries and refuges
Read more about day hiking with children in my guidebook Hikes with Tykes.