Dedicated bike headlights are a good idea because they've got the right kind of clamps to go on the handlebar and the right kind of lens to light up the area right in front of you (not too wide a beam and not waaaaaay out ahead of you, either). I know the flashlight plus duct tape thing has versatility going for it, but "real" bicycle headlights have safety going for them and that counts a lot. Definitely get a flashing red rear light, too. Safety again being the thought -- bike trail or not. Good luck with your after dark riding and stay safe!