I've done 1 day, 2 day and 3 day trips to and around the area.. and
it is possible to do a one day trip.

Leave LAS before people wake up...... stay till the sunset at Grand Canyon and
return late. This will give you plenty of time to spend at the park.

It will take you around 5 hours each way with a reasonable speed and
a stop or two.

I've also done a full circuit from LAS -> Zion/Bryce -> GC north -> GC SOuth -> LAS
This was great!


And there is always Red Rock canyons, Valley of Fire and Lake Mead.

I'd go back to Red Rock Canyons any day for hikes.