We are planning a 4 day trip around the loop from Vegas to Grand Canyon to Bryce and Zion and then back to Vegas.
The other option is to do all the days up in Zion/Bryce area. Wife has been to neither (last time in this area was Arches/Moab for a day with family). I visited the Grand Canyon back 40 years ago.
We would leave LV on a friday (checking out) and have to be back the following Tues afternoon.