I weld in a barn, and have been planning to build an offroad cart. I have a platform where my shop is, so I can roll my current welding cart around fine, but if I want to move away from that, it's all gravel, and a pain. I am going to move up to a Thermal Arc 252i here in the near future, so I will build the cart to suit that. I plan on 8" aired tires, two in the back and skids on the front, and handles that will pull out and be used to push like a wheelbarrow, and push in/use to coil the gun and ground cables on otherwise. I want to be able to push this thing over gravel and semi-rough ground, because that's where some of my welding occurs. I like your idea of a wagon that you can pull, but I do want mine to be short, so it doesn't take up as much room in my shop.