In case anyone is wondering what happened, the winning vehicle is a lawn tractor. I found a nearby handyman special for $50 and after a couple or so hundred more it's ready to challenge the hill.
A few 6x6s in the classified section recently caused me regrets but at least I've been doing something.
A lawn tractor has shortcomings that AATVs don't have. One tiny disk brake that's part of the transaxle won't do a thing if either of the rear wheels slips. It has nice gearing for my needs though, you'd prolly call it slow as ****. I may try converting it to a tracked vehicle. If I do that I might post some pics here but it wouldn't be amphibious and thus underqualified.
What it will do, I hope, is help an old man drag bricks and such up the hill as far as it can, where path-building will take place to go further next time.
Thanks for all the advice! I hope you all enjoy this season and many more.