About Ontario International:
Ontario is a treat compared to LAX. I find LAX to be horribly congested, but flying in and out of ONT is comparably much easier. I avoid LAX when I can.
Several major airlines serve ONT - most fly in through a hub city. JetBlue has a non-stop from JFK to ONT, but it's a red-eye on the return.
If you are planning on renting a car, it's not too bad a drive to the Palm Springs area. I'd estimate 1 1/4 hours or so (depending on how much lead is in your foot - this is S California, and people just fly on these freeways). But traffic is heavily dependent on the day and time of arrival. If you arrive or depart on a weekend, traffic won't be that bad. On a weekday, expect heavy rush-hour traffic westbound (going towards LA) in the morning and heavy eastbound traffic starting in the mid to late afternoon. The rush hour traffic will lighten up to the east of the Redlands/Yucaipa area.