There are none. However, in comic strips and Cartoons, Z Z Z Z represents sleeping and, perhaps, snoring too.
sleep
A word beginning with R for sleep is rest.
sleep place
somnambulism
Another phrase for time to sleep is bedtime. Night Night, Sleepytime, Dreamtime are all different ways to say Time To Sleep.
Slumber is another word for sleep.
A berth.
Awaken? cmf3225
Slumber is another word for sleep.
Nap
I think is 'bed' obvious
relax sleep calm down Repose.