If you are planning on doing larger maps then I would suggest using asynchronous line traces. You could also scan the terrain in sectors adding to a texture atlas.
If you want to use it for procedural terrains then baking data from the sun position won’t work as well (map can have offsets and be at different heights).
You would have to just bake in information that is relative to the terrain and normalize the data.
You could in theory bake in the sun’s path across the sky and set where you could have moss grow, leave snow from melting etc.