The 144k are the first fruits, 12k from each tribe.  They are the ones watching and are ready.  From what I can follow up on that in relation to a dream I had so this is only based on that, they can go anywhere throughout the Earth, and also in heaven.  I think they'll have their glorified bodies here on Earth to let people know what's going on.  (Rev 7 speaks of the 144k sealed, possibly during this time those events take place.)  The next harvest is the two witnesses: Jews and Christians, they are NOW wide awake and aware of what's going on.  The last harvest is the grape-they are thrown in the winepress of God's wrath.  Hope this helps although I'm not Renee, I wanted to briefly tell you what I think it means.

Kari