I did not see this earlier so kind of mute for your plans wayne, but as an FYI - the Grand Circle can be done as Grand Canyon, Lake Powell, Bryce and Zion. I am not saying that the other parks are not great too, but the route I am speaking of is done by million of visitors for a reason. It really is kind of a circle and can be done in a manageable number of days. Stopping by the Trip Advisor forums for those places can help with planning, as well as the Vegas Forum. As we speak I a sure that many folks are planning that same trip for this summer.
I love that route but my fav is always the back to Vegas part of course :-)