how long is the river walk

The River-Walk branches and could become a long walk. It depends on what you'd like to do. It could be 30 min up to for example couple of hours...

Not sure how long but its long enough for the Riverboat. There is so much to do along it like shopping, food, music, hotels.

Also there is water taxis

You could easily walk for a couple hours if you did both sides..

Quite a walk..but once you start enjoy.. you won't care