Sure. As long as you are over 21 no one will stop you from just walking around, in fact you will likely appear to just be looking for a slot machine and taking your time about it. Sometimes, I purposely plot my route from restaurant to my room just so I can scope out any slots having a fun bonus.
Yes, you can stay at a casino hotel even if you have no intention of visiting the casino. Many casino hotels offer a range of amenities and services beyond gambling, such as restaurants, entertainment, spas, and pools.