Suggestions for Best Garage / Valet Parking Downtown?

I'm going to be spending some time downtown in a few weeks, and I'm trying to figure out the best place to park my car for 5 - 6 hours. I know Golden Nugget and some of the other properties offer free parking in their garage with casino validation, but that's usually only for 2 - 3 hours. Are there any casinos / garages that usually permit parking for an extended period of time without asking questions? Or, for a 5 - 6 hour visit downtown, would the best option just be to use valet? And, in terms of valet, do some casinos tend to be faster and more efficient than others?

Thanks!

 

Main Street valet, takes a second, you can walk down the street or take the bridge across to California, by far the easiest. to get in and out of downtown,

 

We usually park at D. Very easy to get in and out of and also quite easy to get back to the strip or head north to the highway. We've never paid for parking - just put a few points on a card and get validated.

 

MSS is the only one I've used, haven't had any problems. $3 and if you gamlbe a bit they reimburse it.