First, with the industrial areas that would seem like trespassing, train as you can, then be as respectful as possible with the people who might end up approaching you about it. If you are careful, and stick to ground-level areas while paying attention to not destroying property, the worst that can happen is that they can ask you to leave. Second, check out the possibilities for drilling individual specific movements at the small areas you HAVE found, absolutely perfecting basic techniques by training them over and over again. This has been a huge help in shoring up some lagging aspects of my game. As far as the playground is concerned, most people won't mind as long as you aren't playing on it while kids are present, or you aren't destroying the property. If they do have a problem, politely explain that you are participating in a physical training method that is for health, fitness and physical capability, and see what they say. If they still have a problem with it, you will have to find another option. Hope this helps at least a bit! Good luck, and keep us updated!
in addition to gears statement about the school playgound, i think its ok to go and train there, just make sure you do it outside of normal school hours, usualy they'll have signs posted saying "no tresspassing outside of hours", but usually as long as you aren't being destructive or trying to get up on the roof its not a problem, and if someone approaches you, calmly explain what you are doing,and that its not a dectructive practice at all, and maybe they might even let you continue to practice there with their persmission, which is a hard thing indeed to come by for us traceurs.
