I can't move forward in workshop mode. I can only move back and to the sides. My forward is mapped to RMB.

RMB appears to have been mapped to rotating objects. How do I remap that, so that the game doesn't override the moving-forward mapping?

Same here I wish they would allow us too remap that type of stuff. So annoying to have too change my forward button back to W whenever I want to build things, or have to walk sideways everywhere. Walking up a flight of stairs sideways is a pain in the butt.

I don't think you can remap those workshop buttons. Using a mouse button to move forward is not even remotely common, so don;t expect that to get changed any time soon.