Finish top 8 at the Area, and you'll get a spot at the Regional, well kinda... If you do the math 8 x 8 = 64, and most gates only hold around 40, so you might get to the Regional, and have to run a pre-qualifier even to get to stay at the Regional. But even if you finish top 10-12 at the Area, you can still send your money, and might get to ride at the Regional, they will post the final list online before the Regional.
Here's the info on this from
http://www.mxsports.com/qualifying/, which I guess you didn't understand:
1. The United States is divided into seven regions. There is a maximum of eight Area Qualifiers in each region. You must first attend at least one Area Qualifier and finish in an advancement position. The number of riders guaranteed to advance to the Regional Championships are as follows:
Northeast 8 South Central 8 Southeast 8 Southwest 9
Mid-East 8 Northwest 15 North Central 8
And then if you make it to the Regional, you have to finish top 7 and you are guaranteed a spot on the line at the Nationals. Again, if you finish top 10-12, you can still send your money, and might make it directly in (like if people qualify in more than one region, multiple classes and have to choose, get hurt, just don't go, etc.). At that point, they use a formula based on your finish and the number of riders at your Regional to give you a "ranking" number to decide if you get in, or make it as an alternate, or none of the above. Again, it'll be posted on their site before the National.
Here is the rule on that from
http://www.mxsports.com/qualifying/:
2. If you place in an advancement position you will then be invited to the Regional Championship in the area in which you qualified. Again you must finish in an advancement position to be invited to the National Championship at Loretta Lynn's. The number of riders guaranteed to advance to the Loretta Lynn's National Championship are as follows:
Northeast 7 South Central 6 Southeast 7 Southwest 5
Mid-East 7 Northwest 4 North Central 6