Got it. No more sanding! Thanks for the tip and the warning. I've also now read the intro post and some of the links thereof.
The wire wheeling suggestion from Daswulf makes sense, but I think I may leave the rest of the surface with the aged finish unless someone wiser than I suggests it's risky. I imagine the old rust is actually a pretty good protective surface and it looks great, in my opinion.
And, FWIW, I did my first bit of hammering today to make some brackets to secure it to the stump. I'm leaning towards the chain attachment method that Essential Craftsman used in this video, as I have all the bits and pieces: