Early prototypes are great, so I think you are going at it the right way.
I am planning on doing the same, but alot of my prototyping needs a bsp in place, so I'm doing all the bsp build tools for now. 3D is a bit harder to dive into than 2d.
But other than that, I'll probably build one skinned mesh and use that for every character and npc in the game, and skip any other fluff and just get it running
