Go to a large parking garage and do laps around each level to start and end your runs. Go to a health club and instead of going barefoot wear aquasocks or if you are daring just regular socks (black is good) so you don't stand out. You could also go to a city/county rec center with treadmills at weird hours and pay the lone teenager working the place to look the other way while you run barefoot on the treadmill for an hour. Or save your money and buy a piece of crap treadmill just for barefoot running in winter a few times per week. Better than nothing.