How much time the bus takes will be heavily dependent on time of day and day of the week, but then, so will any transport alternative. Nonsense like the underground tunnel thingy and the Moronrsil won't get you anywhere near South Point and aren't accessible from downtown anyway.

 

The still rather primitive and inadequate public transportation system in Vegas is why I always simply drive there. And if I lived too far away, I'd fly there (ick) and rent a car (double ick).

 

And FWIW, I've started to just avoid Vegas proper altogether and make my vacay in Henderson. Apart from Ye Olde Yearly Downtown Coupon Run, of course.