You should have been able to provide irrefutable proof even without the $1.1M. Otherwise you just admitted having an unfounded supposition and pretending it's a fact. Again, 25 years is plenty of time to obtain irrefutable proof. I mean it's not rocket science.
Put a camera on your car (or even have a caravan of cars, harder to fake), live stream the video including a GPS, driving along the known route and filming the mile markers until you get to the vast empty field that is that town. Get people on reddit or something to decide at every step which speed to have, if you should flip the wipers, this kind of thing that proves you're live. You can rent a helicopter, I mean $1.1M will cover a lot of expenses.
And once you have irrefutable proof other people will just claim everyone and everything in there is part of your conspiracy setup. I mean that's the go-to explanation for any conspiracy theorist whenever they are presented with any proof, no matter how solid. So if it works for you it should also work against :).
> They'll claim they proved their existence. It does no such thing
You are correct. This will not prove its existence. It will prove that nobody can provide evidence to support the conspiracy theory even after having 25 years to collect it and $1.1M to motivate them to present it.
> they'll only post entries online they find amusing
Of course. The other entries don't exist. And they'll show you irrefutable proof of that only if you offer a prize.