If I choose to drive and park at Las Vegas hotels while I visit the hotel for a show, eating, gambling, etc., is there a charge? Is it much of a hassle to do this?

No charge anywhere I've been. There's valet and self park. The good thing about valet is you pull right up to the door and leave the car there. The bad thing i, you might have to wait 15-20 minutes at the larger properties to get your car back.

WIth self park, you control when you get your car but you have further to walk to get it.

I usually use self park unless I'm running late to dinner or a show. Both are well marked with big signs as you enter each property. With valet you are, of course, expected to tip so perhaps only self park is truly free.

We usually fly in and take taxis or walk, but drove there last weekend and couldn't believe how easy self-park was. Lots of conventions in town, but it didn't seem like many people had cars, judging from the available spaces. Valet was also fine.

What is the customary tip for valet parking at LV hotels?

I usually tip a couple bucks. I know some people who drive their own fancy cars tip like $10 when they drop it off to get it parked very close and away from other cars. I remember at one of the hotels, driving near the valet lot and seeing a Porsche parked up on the grass which was apparently done for this reason.