The Voyager division of the Hoodoo 500 is for racers who participate completely self-supporting. Not only are follow-vehicles not required, they're strictly forbidden.
Here are some general answers to your questions:
1. Voyager applicants must submit a resume. Entry is subject to the discretion of the Race Directors. Although there's no absolute criteria or acceptance standard, a rider should have completed at least some long-distance riding completely self-supported. This could be a brevet series, touring, or just lots of prove-able training. The applicant should also have done at least a few double centuries within the past year.
2. Voyager racers will start at 5am (2 hours before supported solo racers); and have until Monday at 7am to complete the route. That's 50 hours total.
3. No other 500-mile race in the U.S. has an unsupported division; and we suspect the Hoodoo 500 will typically be the only one to offer this category. Many of the routes for the 500 mile races do not have enough services to allow for self-supporting racers. The Hoodoo 500 does. While the other races claim that "safety" is why crews are required - THOUSANDS of cyclists participate in PBP and similar 1200k events every year. 750+ miles of brevet riding is likely a whole lot harder than any of these races. So we think racers who don't want to spend money on crews should be welcome to participate too.