I did the trek up Camelback on a beautiful late Saturday afternoon in March and had a wonderful time and am really glad I worked it in to my quick trip to the Scottsdale area. I did the Cholla Trail as I believe the Echo one is closed right now, and was surprised at how easy it was to park there. You park on the street about 10 minutes from the start of the trail on a main road that borders a golf course. You then just follow all the other people who are walking to the trail or returning.
As far as the trail and hike itself, it was easy if you are in OK shape and you can easily stop and rest at many points. However, to reach the top-top of the mountain it gets a bit more dicey up there. For 80% of the trail you are simply walking up a path, and a lot of people stop near the top and don't keep going. If you do keep going the rest of the way, you are then pulling yourself up rocks, looking down high cliffs on your side, and generally trying not to slip and fall. Some parts of this final stretch I don't think are safe for kids or people out of shape. For anyone else, it's highly worth it to keep going.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.