Modeling frame rails in autocad inventor?

[Rhino]

I'm working on learning inventor and run into a few issues. I'm a few versions back (2008 pro). It appears I have access to the 2011 student edition, but only want to go down that route if it's not possible with 2008. What's the best way to model frame rails? At first the frame generator looked like it'd be fantastic, but I can't figure out how to anything but a space frame with it. I'm looking to model the rear frame rails in two types. One being the stock "top hat" rear rails in a first gen, and then replacing them with 2x4.



On the 2x4, I thought about creating a shape, then shelling it, however I'm not sure that's the best route.