Hi,

With 6 days you should be O.K to do a nice loop from Vegas by heading North on I-15 through St George to Zion > Bryce > Page [Antelope canyon]> Grand canyon [South rim] and back to Vegas across the Hoover Dam. You could choose to visit the North rim of the Canyon from Zion which has less visitors but less facilities and is popular for being more remote.

The NP's campsites are civilised in the main designated areas as such, having shower/loo blocks and there will be many other campers [the reason to book early] so there will be lots of activity and camp fires around you. However if you want swimming pool, gym or bar [or all three] you will be out of luck. You will need some form of a light as there is no lighting or electric hook ups.