You are flying out on Veteran's day and right before Thanksgiving, which is why the fares are high. Jetblue has limited service between Long Beach and Florida, only one non-stop to Fort Lauderdale and a one-stop to Orlando via Austin, so limited capacity fills up quickly.
Try flying American Airlines out of LAX, they have cheap fares right now for that time, and non-stops to MCO or connections via Dallas or Miami.
For your dates, Continental is $317 via Houston from SAN. That's a good fare for that time of year.
It is still a little early and you might see fares drop in July, four months in advance. However, you have even during fare sales, the average price you should expect to pay between California and Florida is $325-$350 a person. JetBlues $386/person is not out of line with reality. That's pretty normal. I fly Miami to Los Angeles 2-3x a month, and even when I get tickets on sale, I never spend less than $300.