Agreed, Oceanside gets busy because of the Marine Corps base. 25,000+ people all trying to get in there at 6:30 to 7:30 every day. Even better to live near or south of the 56 and I5 junction if you are commuting south. But S.Carlsbad/Encinitas are still a reasonable drive, especially if you are flexible on departure times. Whatever you do, DO NOT plan to commute down the 15. EG: I’d rather put a bullet in my head than commute from San Marcos on the 78 to 15 south, or from Temecula via 15 south. Even at 5:30 am the 15 = gridlock.
