Welcome to RCU. And what a project to come in the door with! ! ! !

But this sounds more like a components and structural detail issue than a truly aerodynamic one. It would be better off in either the Scale or Scratch Building forum. Pick one and I'll move it there.

I also suspect you'll need to fabricate most of the stuff yourself. But some parts can be had from suppliers. Plastic or metal spacers as used in electronics can be used as rollers. And then there is http://www.smallparts.com/ for a good selection of components and materials.