Ontario airport was really easy to get in an out of. Flight from Sacramento on the 10th was pretty light, every one had their own row, so getting off the plane was a breeze. Smaller airport, so easy to navigate, posted signs for everything. I got to the airport last night at 6. I have pre TSA and there was a line for it on the ground floor, only 2 people in the regular line though, so not super busy. For Southwest, gates 401 and 402 are a little hike, so give yourself a few extra minutes.
All rental cars offsite, free shuttle (5 min ride). When returning, the shuttle makes two stops. If flying Southwest, wait for second stop, otherwise you are walking half a mile.
Left Ontario at 10 am on Sunday and made Mickey and Friends by 10:35, pretty light traffic. Made a run after conference on Monday, left Ontario at 4 and make Mickey and Friends at 5:20. Edit-forgot to say that all onsite parking was full-parked at DTD as I knew I was going to meet my DD for dinner at get me 5 hours for free.