Good to meet you! I sure like hickory for board bows.
I used to live near Aurora and I've heard [then] that the shop in Pekin had good stuff.
My suggestion, based on experience with my local hardwood supplier, is that you explain what you're building, tell them you're looking for a very specific-grained board (see George's site), and assure them that if they let you pick through the stacks you'll put 'em back together neatly when you're done. That right there has bought me a lot of freedom at at the mill. Also, showing up to pick through the stacks when they're slow is also helpful
Also, you'll want to read some of the existing posts on dealing with hickory's reaction to humidity (growing up in IL, I remember humidity and I don't miss it. If the relative humidity gets above 25% here, I get cranky). Research into how to finish your bow and how to store it to minimize the effects of humidity on Hickory.
That's my two cents. Let us know how it goes!
John D.
Boise