I'm glad you liked the photos! Velvia 100 is now one of my favourite stocks, alongside Provia 100. I also shot Portra 400 during the trip but I wasn't as happy with the results: the low saturation coupled with grey skies made for some pretty dull images. I think that slide film is the way to go for nature, but otherwise I'm going to stick to negative and B&W stocks.
My plan is to shoot a lot of film but not get the rolls developed until years later. That way, when I finally see them, the images will be like time capsules preserving memories forgotten long ago.