OK I don’t do this now, but I thought of it a while ago and tried it and it worked well. Basically, you make a ramp about 4-6 feet long (say, prop an old heavy door, or similar size piece of wood on some logs or 2x4s). Prop it up high enough so that the sled slides back down on its own. Then you can pull it up to the top…and let it slide down. Its a stationary rope pull. How much weight do you want to use? The thing is, you can change the incline here to make it harder. Well, you asked for ideas? That’s an open invite right?
Yeah, something like that might work. I’m picturing an extra long “total gym” looking contraption, with the rollers.