ow do I get to Blackroot without the Train?

I've got it on my map, but I have Dog so I can't ride the train.
How the heck do I get to Blackroot? Whenever I try and click on it on th eworld map it says I need to find a bridge or border crossing. This happens from Darnholm, Tarant, Shrouded Hills, Random areas of the map....

 

If you look at the world map, there is a bridge to the south (and a little bit west) of Tarant. Just click on the map near that bridge and then click on the map somewhere on the other side of it. From there, you should be able to select a course that will take you to Blackroot.

It might take a couple of tries to get the hang of it, but it's pretty simple.

 

You can put either 5 or 6 waypoint markers on the map. You can't reach Black Root from any of those towns because of the lay of the land. Just use the waypoints to follow the river or shore and you'll get there eventually.

Or do it the long way and just follow the river out of Shrouded Hills. Will take forever though.