Welcome to FlyerTalk Joseph. I hope you'll stick around.
I've been as frustrated as you with Hertz and other companies. Not knowing the ins and outs of the various loyalty schemes and reservation systems makes them all "sucky". And taking your complaints up the management chain can be an exercise in futility, as you're just getting closer to the people who designed this cumbersome system.
And now you know why FlyerTalk exists. We study and share knowledge of how to best maximize our travel ROI.
Learn enough and one day maybe you'll be standing at the counter and hear, "Wow, that's a really good deal you got." At which point you can respond, "Hey, your employer make the rules. I'm just playing the game."*
And if this is a future itinerary, we still might be able to help you get a car in Vegas. If you'd like us to help, post your dates and times of flights.
I just did almost the same itinerary (Vegas, Sun through Wed) and redeemed points for a Chrysler 200 convertible. I know you want a Prestige. I'm not certain that renting for a week and returning early would work. Probably it would. But there still might be ways to reserve a "weekend" if you start your reservation before noon on Sunday.
*I overheard that line at a rental counter, I didn't originate it. But I've certainly adopted it!