For pool, go to Griff's. There is also the Cue Club, which seems to have some action, but it has been a little sketchy/dirty. Bangin Ballz is a new room with Rasson tables, south of the Strip. Walter's Billiards is also new, and has been discussed here. There are several other rooms, maybe including a mostly carom room.
I've heard recommendations for the Mob Museum.
Nature stuff to see in the area: Grand Canyon, Hoover Dam (you walk inside and can look out from half way down the face), Red Rock Canyon, Valley of Fire State Park. For cacti and chocolate together, Ethel M's in Henderson makes fancy chocolates (w/tour) and has a large succulent garden. The M is for Mars.
For accommodation, I was thinking of staying at the (new) Sahara. Their rates looked pretty good, the resort fee is low, and they are at the north end of the monorail. When something was happening at The Rio, I stayed next door at the Gold Coast, where the rates, people and food were much, much better.
I have also stayed at a condo complex in a 3-bedroom suite, a mile or two off the Strip, for about $100/night. Hilton is trying to sell them as time shares or something, but you don't have to attend the "please give us your money" talk. Booking.com lists places like that. I think that will only work if you have a car.
About the strip, it's hard to not feel ripped off at the big casinos, partly due to the fact that there are only three brands. What you can expect:
A "resort fee" of $30 to $50 per day suddenly appears on your room rate when you check in. That's because you might use the wi-fi and towels. The reservation sites sometimes don't happen to tell you about this.
There is no coffee maker in the room. The limited-service Starbucks downstairs will sell you a cup for $5. Or maybe $6 now.
There are no water fountains in the casinos, even though you are in a desert. Bally's is willing to sell you a 10-ounce bottle of water for $8. Really. My briefcase was inspected for water smuggling.
Parking used to be free. Some casinos now charge $20-$25. For a while, you could get free parking at The Tropicana, but they solved that by tearing it down.
The buffets used to be great and not too expensive. I last tried one when I was staying at the Luxor (= Mandalay Bay poor relation) and for $33, there was almost nothing I wanted to eat. In general the casino restaurants will not post the menu outside -- sticker shock problem -- but you can ask to see one.
Once you are on a casino/hotel property, they make it really hard to go elsewhere. You have to walk a long, long way.
I first went to Las Vegas in 1969. Through about 2005 you could get reasonable deals, and then the corporations pushed out the mob (or something like that). These days, they get most of their money from "hospitality" and not innumerate gamblers, so your vacation is not financed by someone else.
One example of how the value has gone away: I complained to Mark Griffin about the costs/values at the Rio, especially for food. $4 for a small, unripe banana at the CSI/BCAPL/USAPL tourney snack area seemed high. He said he had talked to someone in food service there. They were not allowed to spend more than 10% for the ingredients for a meal. The restaurant industry standard has been 30% for ingredients. And that 10-ounce bottle of water mentioned above cost Bally's less than 20 cents.
Be careful in any cash transaction. Sometimes the change may not be quite right. And if you take an actual taxi, know what the charge and route should be or compare to Uber/Lyft.
I just remembered a good deal I encountered at Mandalay Bay at a pool tournament (of course). The beer was cheaper than the bottled water. Water -- $6 for a bottle, Michelob -- $5. 2019? US Open? I try to keep my wits about me when I'm around pool players, but I went for the beer.
