I use a lot of Sapele outdoors. It holds up very well, routes excellent. I use it for most wood signs, all exterior millwork. I also use a lot of HDU that I route for other signs shops. The HDU is excellent for outdoors, but you need to take into consideration of how it will be mounted as it's not structurally strong but paints well and holds up to the weather changes. Downfall to HDU is it is quite pricey.
You would need to have some ideas to be able to narrow down some other possibilities