Every diner should be like the Peppermill. It's has its own parking lot which is and nice and can give you a gauge on how busy it is.
I was there during the week or breakfast so it wasn't too busy but I heard it can get busy there.
The Lounge is to the left and the restaurant is to the right. It's a diner, Vegas style is my best way to describe. I didn't go into the lounge but I did notice a bar right inside. Of course there are the slot machines by the door as everywhere in Vegas.
The restaurant is great. All the seating is booths or counter tops. Classic diner style. The counter you can see the food be prepared and can you track your food as it comes out. Breakfast was great. Portions were huge. I didn't quite finish my meal.
Service was great too. Just enough attention.
There are TV's hanging throughout the restaurant portion as well.
They are open 24 hours and the menu is diner options, breakfast, sandwiches, hot entrees, etc. I only had the breakfast but I'm sure the food in general is pretty good here.