Here's a plan for now. Early April. Thoughts, suggestions..
Day 1- Fly into Vegas Noon. Check out sites, walk strip, dinner. Stay over.
Day 2- Drive to G.C.(maybe stop Hoover, time pending) Half day at South Rim. Stay In-Park.
Day 3- Hike/Explore
Day 4- Drive to Zion- half day in park.
Day 5- Zion -full day.
Day 6- Zion -half day. Drive Vegas -maybe check out Valley of Fire.
Day 7- Relax- any unfinished Vegas- show/dinner.
Day 8- Depart.
More time spent somewhere? If plans change on the go would it be risky to call Zion area(Springdale) and book a room day or 2 in advance? Suggestions on G.C. lodging if in-park isn't avail(checking continual) . Thanks friends.

Sounds like a good plan. When it gets to be about 2 weeks before you leave, the lodging in the parks will free up and you can make a reservation in say Tusayan that can be cancelled without penalty for insurance.

Check www.weather.com for the 10 day forecast to find out what weather will be doing. You know that you could do your loop in the opposite direction also if it turns out that works better for you.

Have a great trip.

That sounds like spring break time so lodging might be tougher to find but keep trying.

Maybe skip Zion altogether and go to Sedona? Or try to add a stop at Bryce if you're set on Zion, there will be snow on the ground but will be a different experience than most people get in summer.

Thanks. Those are 2 other thoughts I had. 1) Going the opposite route, Zion first and 2) weather in Zion. Is it highly likely to be cold/snow on the ground?
Haven't really looked at Sedona. What does it offer as opposed to Zion. If do go to Zion don't want to press my time too much by going to Bryce. Had to chose one on the route.
Thought about Spring break too. Is it that late in these parts? It's usually in March here(SouthEast) But then again the thought of snow in April(or anytime really is foreign to me. Thanks again. Open to any thoughts.

You itinerary looks good.

Given that Bryce Canyon is so close to Zion, it may be worthwhile figuring out how to add in a day there. It's very much worth a visit, as are Grand Canyon and Zion.

Unless it is unusually cold in Zion, it should be fine for hiking in April. We have been there in both Feb and April and there was no snow in the valley. Bryce was another story, it had snow in late April on the paths.