You don't have to guess. You can calculate your minimum right now.
1 Play! Point per battle road
2 Play! Points per City Championship
3 Play! Points per States
5 Play! Points per Regional
The pokemon.com website indicates that there will be other ways to gain play points too but does not go into the specifics.
Lots of players will already have accumulated 10 Play! Points and once you have that minimum you are able to take part in USA Nats. Once you have that minimum it no longer matters exactly how many you have.
I do wish that some more details would be announced but I know that POP won't announce until they are certain they can deliver.
1x Regional + 1x City + 3xBRs = entry to Nationals.
1x Regional + 2x Citys + 1xBRs = entry to Nationals.
1x Regional + 3x Citys = entry to Nationals.
5x Citys = entry to Nationals.
2x Regionals = entry to Nationals.
1x Regional + 1x States + 1x City = entry to Nationals.
2x States + 2x Cities = entry to Nationals.
1x States + 2x Cities + 3x BRs = entry to Nationals.
etc..
And I'm sure there will be more ways of qualifying because the website indicates that there will be.
Play! Points said:
{from the pokemon.com website}
Beginning in early 2012, we’ll be implementing our Play! Points system to replace the existing Rewards Program. Players will earn Play! Points by simply attending qualifying Play! Pokémon events, with "destination events" earning you even more points. Play! Points will reward you for being an active Pokémon player—win or lose. Some special events each year will require Play! Points for entry. Plus, the top Play! Point earners in each division will earn Player of the Year honors for their dedication! We’ll have more details on the Play! Points program in the coming months. Until then, don’t worry; all qualifying events you attend in the months leading up to the launch of the system will count toward your Play! Points totals.
What Are Play! Points?
Play! Points are points you can earn by simply participating in qualifying Play! Pokémon events. These events include Leagues, Tournaments, and Championship Series events. When the program begins in early 2012, you’ll be able to review your Play! Point totals and see where you rank against other Play! Pokémon Members worldwide.
What Are Play! Points Used For?
Play! Points will reward you for what you love—playing Pokémon! As an active Play! Pokémon member, we want to reward you for your dedication and ongoing participation.
Play! Points replace the current Player Rewards program, where players can earn cool Pokémon stuff just for playing. During the season, the most active players will now be able to earn more Pokémon goodies than before.
Pokémon Organized Play will award the title of Player of the Year to the players from each age division with the most Play! Points.
