Trying to book a car for pickup on Sunday evening at CVG, return Wednesday morning.

The website says nothing available.
Called Hertz to try the PC "Guaranteed Availability" feature, but they can't see a Hertz location at CVG except for the FBO (which is serviced by Hertz CVG)
Tried calling the location but no one answered and the call was disconnected after about 20 rings.

Hertz.com will let me book a FBO pickup (and looks like I can enter arriving flight information)

Anyone know what's going on with this location?
Any pitfalls of booking for the FBO (besides having to get myself from terminal to FBO)?

Where I need to go is close enough that I'm contemplating just not renting a car and Ubering but I like the flexibility having my own set of wheels gives me...