On a single day, I would take this route:
Down Flamingo to Sam's Town; self-park behind the building
A little way back on Flamingo, then Hwy 95 to Sunset Station - have the buffet
Short hop down 95 again to Lake Mead Parkway, turn left, to Fiesta Henderson located on the right just after the underpass
Up Lake Mead Pkwy/215 to Green Valley Ranch - Park on the roof of the 215 garage, unless it is a very hot day. Even better buffet.
Then back to your hotel.
Next day:
Take one of the highways - or - take Flamingo or Charleston to Red Rock Hotel & casino - eat the buffet
A little further up Charleston is the Red rock area. There is a short drive and a long drive to see the Red Rocks.
- bcc