I consider myself an iron-bottomed driver, but my personal best is just over a thousand miles in 26 hours of continuous solo driving. You are proposing to do that, do it again without a break, and then do half of it yet again, all while trying to keep three young children motionless and entertained. There will be no time for overnight stops if you truly plan to get from SoCal at 0400 Thursday to Kissimmee at 1600 Saturday. I believe your chances of pulling this off are, as they say, slim to none. Even a "full 4 days" is precious little to try this and still maintain family harmony. Please reconsider.

AZBuck