You can probably rent from Hertz at Harrahs Reno. Having said that, the hotels have complimentary shuttles to/from Reno's airport. Rental car counters are located inside Reno's airport.
The first time I visited the area, I took the South Tahoe Express to/from the Lake and rented a car from Hertz at Harrahs Lake Tahoe for 1 day of my trip.
I always rent at the airport. The airport taxes and fees are nowhere near as high as in Vegas. In fact the prices at the airport appear to be lower then off-airport. As MissL7777 said all the casinos have shuttles but the times are no real convenient. If you only plan on cavorting around downtown do not rent a car - take the Harrah's shuttle. However since the best casinos in Reno (Peppermill and Atlantis) are well down Virginia Street from downtown a car is recommended if you want to hit those places. Also a trip to Carson City and Lake Tahoe is almost mandatory so a car would be the most convenient way to make that trip. We really like the area and would retire there if it did not snow in the Winter. Enjoy.
Reno has excellent public bus service between downtown and the two big casinos down Virginia street, Peppermill and Atlantis. I've used it often and the service is frequent and quick. RTC Rapid is the name of the express, and RTC Connect is the name of the local. Official info
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