Johnny, it is doable, but you want to make the structure something like a normal site that googlebot or others would see. They know how to spot doorways. Look through google for the domain mentioned here. 6000 pages in the SEs, but most of the doorway pages don't have any "content" next to the listing, which means either not indexed yet, or not indexed for other reasons. There is a trend.
Build real directories with actual html in those directories, and things work a little better.
Alex