For GSR, you can usually get the cheapest rate by walking into the hotel without a booking and haggling. It's definately worth getting one of the upgraded rooms as the old rooms are shocking (I wouldn't let my dog stay there). You do need a car but assuming you're not going to Reno to 'hang out on the strip' then it's better to stay out of the downtown area anyways.
The GSR pool is a bit tacky with their Nicky beach theming and is very shallow. Don't go near the 'day beds' out by the pool area - people are often caught having sex on them! Icky!
The restaurants in teh GSR are also pretty good but expensive.