The Ac unit will def cover the noise of an td-100x...a tall oscillating fan, I'm not sure, it may sound similar (depending on how loud your oscillating fan is). I've never run mine in an occupied part of the house...most often I've had it installed in the attic (right above my grow closet), and I used it once in a garage - so I can't say whether visitors will notice if it's running without anything else going in the room at the same time. If you have it installed INSIDE your cab (as in your diagram), I would think the noise would be hardly noticeable...especially if you have another fan running in the room (or, better yet, a window AC unit).
Also, I usually run mine with a variac fan speed controller, and I didn't need to run it on full speed very often when I used it with my small cab. When I grew in the full-sized closet, I had it at max speed during flowering in the summer months. I had central AC in the house, so it didn't really get that warm in the house anyways...but the volume of the closet was almost three times that of my small cab, so it just wasn't that easy to exchange the air in the closet as fast as I wanted to unless it was at max speed. Since the fan was mounted in the attic, I certainly never heard it over the house central AC. In fact, it was barely audible even when the AC (or furnace) wasn't running.