Making the jump...
 

Just wondering if I could get some knowledge or input of the likelihood or possibility of someone who works for Great Lakes, PenAir, Silver Airways, AirChoice One, etc to make the jump to a legacy, major or LCC?

Llc is where I would aim.especially if you are around the 2500 hrs mark.

About the same as any other competent regional pilot who:

1) Has the minimums
2) Can get the invite to an interview (toughest part, I'd wager)
3) Can pass training

Know a Dude at lakes who got interviews/offers from Allegant, Frontier and ATI, and he has peers who made quick stops before heading to legacies.

Have some friends who jumped over to Frontier. So far they love it.

Meet minimums and you have just as much of a chance as anyone else, my question would be why go to Great Lakes when you can go anywhere else? If you don't get a call from legacy then you're stuck at Great Lakes when you could be somewhere else