I'm planning a 10 day roadtrip in late July/early August from Los Angeles to the Grand Canyon. The current plan is to also stop at Zion and Bryce but we're open to suggestions if there are better spots to see along the way. Together we'll have 5 kids between the ages of 5 and 10 so we're looking for stops that will appeal to kids this age and minimize long stretches in the car.

I'm looking for tips on where to stop, where to stay (combo of hotels and car camping) and what route to take. I'm also looking for recommendations on must sees and must dos in each park since we have a decent amount of time to cover the distance. The current route I'm considering is:

1 - Los Angeles to ? (Hoover Dam?)
2 - Vegas to Zion (2 days)
3 - Zion to Bryce (2 days)
4 - Bryce to Grand Canyon (3 days)
5 - Grand Canyon to Los Angeles (uncertain about stops along the way)

Other attractions I'm considering are the Petrified Forest and Slide Rock but I'm not sure if these are close to any of the other spots we're visiting. All tips appreciated!