Definitely recommend GC, we hired some Dodge Chargers and drove the old route 66 to GC via Hoover dam etc. but this takes much more time (we spent 1 day / 2 nights in GC). We did a cycle route around the edge, and then had some beers sat on the edge as the sun set 
The helicopter route, as mentioned above, is also supposed to be great!
Personal highlight was the gun range, if you're interested in that sort of thing. We used a company called Shoot Las Vegas, who drove us out to a range in the desert (~45min drive) I've shot a fair bit in various places (indoor ranges elsewhere in the US, outdoor in Prague etc) but these guys were fantastic. Massive set of weapons to shoot / choose from, really helpful, happy with whatever as long as you're safe / not being stupid. Completely fine to full auto a whole AR mag down range and they also have boxes of mags ready to go, so just pick your gun and there's no waiting around. We also shot a Barrett .50 cal here, as well as stuff like the AWM. 100% recommend.
Small piece of advice for gambling, personally I found it better to use my allocated "gambling fund" on one session, rather than trying to stretch it over multiple sessions. I feel like you get a better experience overall, as you're at Blackjack (for example) for a decent amount of time; allowing you to get into the flow, get some drinks to the table, speak with the table staff etc.
The helicopter route, as mentioned above, is also supposed to be great!Personal highlight was the gun range, if you're interested in that sort of thing. We used a company called Shoot Las Vegas, who drove us out to a range in the desert (~45min drive) I've shot a fair bit in various places (indoor ranges elsewhere in the US, outdoor in Prague etc) but these guys were fantastic. Massive set of weapons to shoot / choose from, really helpful, happy with whatever as long as you're safe / not being stupid. Completely fine to full auto a whole AR mag down range and they also have boxes of mags ready to go, so just pick your gun and there's no waiting around. We also shot a Barrett .50 cal here, as well as stuff like the AWM. 100% recommend.
Small piece of advice for gambling, personally I found it better to use my allocated "gambling fund" on one session, rather than trying to stretch it over multiple sessions. I feel like you get a better experience overall, as you're at Blackjack (for example) for a decent amount of time; allowing you to get into the flow, get some drinks to the table, speak with the table staff etc.
