Unless you rush, you can spend a good part of a day walking from casino to casino, playing craps (so you get $1 chips and maybe 25c or 50c at some places)

Then Fremont Street Experience at least one night.

The Strip walk will take a couple of days. North, Middle and South. In other words, someone isn't going to run out of places to go to easily.

If they have a rented car and feel like it, there Jean Nevada (two casinos) and continue on to Primm with three more. Nice half day trip because it's all Interstate or shuttle busses. Primm has one that goes over the Interstate.

Laughlin is fun to visit.

There's a whole group of East casinos around Sam's Town.

You understand this is just casino chips and token collecting stuff.

You could spend a month sightseeing around Las Vegas and not see everything.