I cycled down the Baja Peninsula between Thanksgiving and Christmas in 2016 and enjoyed my trip.
There is a reasonable variety of traffic density with some areas in the north and around La Paz with a lot of traffic and some areas in the middle sparse and desolate. On average, the shoulders were OK in the populated areas but I also encountered some places with narrow shoulders and moderate traffic but including larger trucks where I found myself watching my mirrors and getting off the road once or twice.
One of the worst areas was under construction so might be better now. However, given three wheels tracking for trike I might anticipate you'll have a day or two (not all the time) where you might need to watch mirrors and adjust to traffic. The rest of the route will be better.
