All we have is 1 solar panel installed by Escape, combined with the dual batteries. We have 100% boondocked over the past year and never had a problem running out of power, even on cloudy days or when the trailer was in the shade. The one panel has provided more than adequate power to run the furnace fan, exhaust fan, power awning, power jack, water pump, radio/CD player, light up the inside at night, and charge our devices. We do not, however, run things like a television, electric coffee maker, or microwave.
It would all depend on your options and how much power you think you'll need as to whether you would need additional solar. I've actually been amazed at how well the 1 panel does and how quickly it charges the batteries in the morning. It's like running out of power is just not something I have to think about. Others will report they had Escape add a second panel, or they use a portable system, which gives them a lot more capacity. Again, it depends on what options you have, how you'll be using them, and what sort of camping you're planning to do. The Baja plan sounds like a ton of fun, by the way!!