cycle.travel doesn’t yet do routing in South America I’m afraid, so you’d be better off with RideWithGPS! You might find c.t useful for finding quiet low-traffic routes in the US and Mexico though.

Fabiano, that's quite a big trip! My suggestion would be to be familiar with several different planners as each have their own advantages and disadvantages that you'll be likely to need on such a trip. 

My recommendation would be to include Osmand on any list. Not the easiest to learn but works offline. 

Thanks for the info guys!

In the end I think I will "specialize" on RWGPS. In Europe many people use Komoot, but I think it is inferior.

@Richard. Mexico scares me to go beyond Baja, for the US I will only need to get out of San Diego to enter Baja.

@Hobbes. Thanks for the info. I've been using OsmAnd for a long time precisely because you don't need the data.