State what it is you can do, and how it can be tested in a reasonable way. There is only one prize.
I regularly travel between Oregon & El Paso, Texas (left NC 10 yrs ago). If a venue is reasonable for me I will travel. If not, the burden of travel is on the claimant.
Addendum...
It's a time-consuming process to write up a formal test protocol and contract. I urge people to first consider an informal test, where we meet and they attempt to show whatever it is they think they can do, under more relaxed conditions and where the protocol can be altered on-the-fly as they come up with particular objections. Most people simply have no idea how a proper test is conducted, and they are so self-deluded by their own sloppy methods that a "training session" gives them the opportunity to see just how far off they are. So far, only 2 people have gone straight for the 25k, the rest opted for the informal approach. None of them did better than guessing, and none of the informal applicants ever came back for the prize.