Argh... Doing lakes and rivers is proving difficult. Especially that one in the far north - if I just run the Fill Basins command, that entire section up to the sea is completely filled in and flattened. So I'm trying to cut a channel through the mountains and it's very slow going. I didn't mind it flattening in the tropical zone (makes for a better Amazon river with river paths filling in the whole area) or the southern small lake. But that northern one is just too big to convincingly be a flat plain.

Also, I don't know if it's a function of the fractal generator I chose or not, but if I run the 'Fill Basins as Lakes' command, it just floods the entire place with lakes. Basins all over the place. Same issue if I fill with land, flat plains everywhere. So, lot's of manual corrections.