Las Vegas native here.
I've never done the Grand Canyon tours... so no input there, sorry!
Hotels
You get exactly what you pay for. "Oh man this is a great deal!!!" No it's not. The hotel will be run down, decor from the 70s, and just clean enough. I've stayed at MGM (and signature suites), Vdara, Aria, Luxor, Excalibur, Tropicana, Mirage, Venetian, Palazzo, Monte Carlo, Mandalay Bay, and Caesars. I've stayed in a ton of the hotels off strip too. Overall, off strip hotels are actually cleaner on average for what you pay for. Even within the same hotel, the price range is directly correlated to the quality of the room.
My overall pick would probably be something like Aria. Yeah it's $300/night but you're pretty close to the center of the strip, all the rooms are nice, and it's a super high quality hotel.
Food
It's Las Vegas. Do a buffet. Get all you can eat sushi. I actually love our Mexican food too, but go to North/east Las Vegas where people speak Spanish more than English and you'll get some authentic (like grilled out of a steel drum and freshly made tortillas) Mexican.
Also, get tapas at Firefly, just off the strip. I'm actually not a huge fan of this place but literally every person I've ever brought here from out of town told me it was their highlight of the trip for food.
Be outdoorsy
I love the Red Rock Canyon for scenery and trails. Lots of desert stuff to see. Last time I was up there, my favorite trail was closed but it could be open now. The peak of turtle head lets you see the entire Las Vegas valley and give a gorgeous view of Red Rock Canyon. But that's a 4 hour hike and a 2000ft climb, so be prepared.
Mt Charleston also more trails and some mountain forestry and wildlife but the views are sort of lacking and there's not a ton to do once you're up there.
Make your way down to Hoover Dam and enjoy the water down the river. There's even a few hiking trails down the river of the dam. They're pretty quick and one of them starts inland and ends at the river near some hot springs.
Drink
Best bars are downtown for sure. At least the ones within walking distance of each other. Just east of the Freemont Street Experience (huge ridiculous overhead marquee for light shows) there's a TON of bars and food places. This area has really flourished and this easily outpaces the strip for drinks and easy food. Downtown cocktail room is my favorite place down here; they make fantastic drinks if you're into IBA cocktails and not just rum and coke. Frankie's Tiki Room just outside of the downtown area used to be my favorite place to get hammered, but you probably won't want to be driving after leaving there.
Cool shit to do
Vegas has more than just Cirque du Soleil and Backstreet Boys on the strip. Obviously, if shows are your thing, go see one. For Cirque, I've seen Beatles Love 3 times; I adore the Beatles and this show is perfect for it. For normal ass acrobatics, watch O at Bellagio. It's quintessential Cirque du Soleil.
For other stuff, you can go to the pinball museum, go indoor skydiving, ride the worlds largest observation wheel, throw axes at targets indoors, have a club/golf experience, shoot full auto machine guns, race exotic cars around a racetrack, zipline from a hotel roof, and jump off of the Stratosphere tower. Google "things to do" in Las Vegas and I promise you it's not just a list of strip casinos and restaurants.
The Las Vegas Strip is a scam, go downtown for drinks and nightlife
If you want to see it, drive down it slowly with your windows down at night. With the lights on the strip is a sight to behold, but not one to walk down. It's brutal. Figure out what casino has the stuff you want to see and drive there. There's absolutely no reason to be walking up and down this god forsaken street in the middle of summer.
For nightlife, Las Vegas is literally second to none if you like the club scene. Clubs are a billion dollar industry here and people like Kaskade, Tiesto, Calvin Harris, etc are basically residents. I for one don't dig clubs, and that's why I generally recommend going to the Fremont East district for nightlife.
From time to time I see Vegas threads and always meant to write a personal list of things to do. I'm sure I missed a lot of stuff but this is my personal baseline.
