Up or down..... if you have a framed floor - not concrete slab - then see if you can route the vent pipe down and out and use a downdraft. Not ideal but they work. Up means opening sheetrock to place the pipe inside a channel between floor joists to the outside. I would get a stud finder and an ice pick to explore floor joists directions before going too far. They are often blocked by other utilities or perpendicular framing. Also consider cooking surface. Gas places a LOT of heat, carbon monoxide, grease, and other stuff in the air - really need a large pipe and a big fan (look to appliance specs for recommendations). Induction - cooks faster than gas, better control than gas, much easier to clean than gas - does not put a lot of stuff in the air....Also talk with code people in your city about make up air - this keeps gas fumes from water heater from back-drafting into your home. Best of luck.

Thank you this will help my husband a lot.