What makes you think those gate assignments are correct? I'm based at JFK and I wouldn't trust them the same day.

Also, no... depending on time of day, the transcons are almost never in the low B20s. Often those are KLM flights to AMS. LAX flights are often in the B30s, in my experience. This journey from A to B has been well documented on here. I could be a lot of walking. There is a shuttle that connects A9 with B54 and often that's the way to go. Nice tarmac views on the way as well.

Although, if you're a lounge person, the Amex lounge is midway across the central concourse, right between A and B. There's also a brand new skyclub at A8, and an older huge skyclub at B31.