Thanks for the input! Looking for any advice I can get.
I actually found that the ductwork goes up into the ceiling above the kitchen, then out the through the back wall of the house. Guess it doesn't really make any difference where it's vented really.
For anyone who's done a kitchen remodel, how do you install a cabinet above the range if there's an existing duct in place? Just cut out the back of the cabinet so it fits around it? I guess another possibility is just to do one of those decorative wood or metal surrounds and just give up that space. Decisions, decisions. . .