Welcome aboard James. In my opinion, the S4S from the box stores is not only expensive, but the few times i've used it, it's needed to be milled anyway.
Can't speak to the Indy area, but in South Bend we have Johnson's Workbench, a small mill in Michigan City, another "boutique" mill in the Buchanan Michigan area, and rough cut comes up on Craigslist on a regular basis. With a Woodcraft and Rockler store in your area--might be worth stopping in at those two and ask the question about local sources. The little mill in Michigan City is actually an add-on business for a tree service, so calling a few tree services might be a thought.
Edit--from Indianapolis CL, quick scan of "Materials"--http://indianapolis.craigslist.org/mat/4356593315.html I know nothing of this person, and have no personal interest, just an example of a source.
Last edited by greenacres2; 03-25-2014 at 06:11 AM.