get 2 people, each holds a pole, and pull the person. or u could build like a small ramp of decent size and put some fake grass or carpet grass stuff w/e, throw some snow on and yur set.
i would say the pulley idea is best. get a fairly long rope, hold one end, have it go around the rail above a cross beam, and have a friend run back, bike, w/e towards you with the other end. should work good
you can also use a ladder..salnt it at like a 30 degree angle and ski down it.. it gives you hella speed...the only problem is you cant use new skis because they might not like it
Buy a wakeboarding winch. they cost around 1700 and can hold 2000 ft of rope and pull you up to 25 miles per hour. Its a good investment if you would use it alot
top secret idea ive only seen done a few times before.
you use NO incline or drop in. then if there is side walk which there usually is, create a snow run way. stand on a skate board with your skis on (facing normally like a skateboard stance) and have some one push you in really fast towards the snow runway. when you hit the snow the skateboard should stop and you have to jump off and turn 90 degrees as you move into the runway. ski up and slide as normal. takes some tallent and practice, but it can work extremely well.