When I set up my wedding cake that is half styrofoam and half real cake, how do I do that? I'm guessing the bottom few layers that I do that are styrofoam can just stand by themselves w/no support(dowels or cake separator plates) but then when I put the next two real cake layers on top of that should I just set those up as if they're the only ones and put dowels through them and cake separator plates and all that? Also if I want to use my styrofoam cake again and i'm decorating it in buttercream, do I need to cover it w/saran wrap first?

Great questions. Thought I'd give you a bump.

Yes the styro does not need to be doweled. The real tiers with the exception of the cake that is directly on the styro. So stro,cake board, cake, dowel, cake board,cake.

With only two layers of real cake, I wouldn't worry with doweling the styrofoam. However, one of the cakes I did had four layers of real cake on top of a styrfoam layer, and I felt that was enough cake weight to warrant doweling the styro just to be safe.

I wrap all my styrfoam in saran wrap and then parchment paper so I can reuse them. I just wrap them up like presents; the round ones are trickier but worth it since styrofoam can be so expensive.

Just remember, if this is a paying cake, charge for the dummy cakes too! They cost just as much as real cake in both "ingredients" and labor.