Hello Klet!
Coming from Phoenix, I'm assuming you'll be taking the 10 a majority of the way. I live north of Long Beach in the Santa Monica area, but the 10 can be brutal during peak commute hours and especially nutty on Fridays. The rush hour never seems to stop on a Friday, I suspect because many people either arrive to work late after Thurs night fun or leave early to start their weekend. If possible, try to make the trip on a Thursday. The traffic is much more predictable then. LA area rush hours Mon-Thurs are roughly between 8-10am and 5-7pm. If you do arrive on Friday, I'd suggest getting here either before 3 or after 7. (Perhaps someone who lives a little further south can help with the specifics about the Long Beach area.)
As for the Long Beach Convention Center, unfortunately I've never been. But, friends who've been attending AX for years tell me it's MUCH smaller than the Anaheim Convention Center which to me means even longer lines than last year's AX. (I'm going to stay positive though and hope they are a little more organized than last year regarding check-in and event seating...

) I went all four days last year, and enjoyed every bit of it. There was a significant drop off in attendees the last two days. If you want to avoid crowds, those are the days to go. Of course, most of the "major" events take place the first or second day, so I suppose it's really up to what you want to see and what events are important to you.
Hope this helped at least a little bit! And if anyone has ANY suggestions on how to avoid an insane check-in line, well, it's not too much to say I will love you for all time.
-Megan
Clever is as clever does.
-Ani Difranco