My question is: Where geographically in the U.S. is the safest? If scientist are aware of meteor locations and the estimated landing areas. And according to christian beliefs, the left behind theory. If left behind, what should I do?
The Bible only indicates one place where God’s people will be gathered to safety before the End Times catastrophes described in the Book of Revelation start. Joel 2:30-32 tells us the location of this place of safety from the same the blood moon and other heavenly and earthly signs of Rev 6:12’s 6th seal.
As you might guess, that place is not America, but the same place that the 144,000 will be gathered to and sealed (Rev 14). If you are left behind in America at that point, there is still hope as there will be survivors everywhere (Zech 14:16). However the best plan is to start understanding and accepting that you will one day be faced with the decision to listen to the call of the promised End Times Elijah to move to Israel from America (as Revelation 17-18 and Jeremiah 50-51 explicitly say).
As these things take long dedicated study to piece together I recommend my book Planet X in Bible Prophecy to help you understand.