Forced Perspective [HINTS NEEDED]

Hello! I'm kind of newbie here in this Stage 32 network, so I'm sorry for any misuse of the website. I'm a brazilian filmmaker, currently working on an expressionist short movie about some cocaine-addicted guys, and I want to take a shot where two of the characters are walking down a dark road, only they and the white stripes of the road are visible, and then when the characters approach the camera, one of them sniffs the last stripe, that's actually made of cocaine. I'm with some ideas of how to make the scene, but we have the location only for a few hours, and I dont know if my idea will work. We have a 15m (50ft) long darkroom to shoot it, a t3i canon camera, and a 10mm fisheye, an 18:135mm and a 300mm lens, lights in a catwalk 3m (9ft) above, and 3 ground mobile light with different power levels. Any hint about how to make it happen, regarding the stage, the lights, the camera, the actors (pretty much anything) is most welcome. Thank you in advance.