I think you just need to get lucky, unless you rent a larger SUV class where any possible vehicle has 4WD. As previously mentioned, no guarantee of AWD on even the smaller SUVs/crossovers.
I got lucky (definitely a bunch of dumb luck) today on my drive JAC-SLC. Originally booked a standard sedan (probably a bad idea to begin with), and asked at pickup if they had anything AWD. Turned out they needed to get a Suburban down to SLC for tomorrow morning so they were able to send me with that.
Nice! Trying to avoid the big ass ones. Drove a Suburban for several years. Great for hauling kids and gear, sucked to use and park in day to day stuff. But I guess we will see what we get!
Thanks to everyone for all the info! Lots of ideas to run with. :beer: