We have a snowkite-school at a small skiresort in the north of sweden, and i have been playing around with the idea of pulling people. Last year I towed some friends to the top of a little hill just by them attaching their skipoles to my HP-leash line. No speeding, just slow towing.
I am going to ask the ski area if they have an extra "button lift" from one of the kids lifts. I imagine having a few meters of line on it with a climber carbine hook on the end, and just click it into the back of my harness and voila, a lift for peole =) Should be fairly safe, much like the normal button lift. If you fall, you loose the button. This way it will be easier for people to get towed, and I also imagine it will look cool!
It super easy to do, We tow Photogs behind us all the time with just a leash or two, from shot to shot. I would not over think it. If you feel you can tow her then go ahead and try. You can make enough drag to "hover" between the kite and a heaver person. But if you use the kite correctly then it is not a issue. The harder the snow the easier it is. I have towed students, broke down kiters, Photogs, and friends and family on and in everything from ski, boards and sleds n tubes it is lots of fun.