Drearyweather, let me be clear the scriptures in the original Greek do not say they will be kings. Yep not kings, the King James Bible and the JW Bible has it wrong. Not only the scriptures in Revelations but all other scriptures in the New Testament that make it seem like they are kings.
And as for reigning as priests with Jesus, the kingdom of god according to Revelations comes down to earth so the throne he sits on could be on earth. But this again is just arguing semantics.