ADCO is in Ohio, and is one of the many good guys here on ar15.com
www.adcofirearms.com they have a large stock of RRA stuff. If you decide to go with RRA, make sure you avoid the "tactical" carry handle. It is useless, and since you are planning on getting a optic sight, it will only complicate things down the road. Instead spend the extra money now and get a LaRue or LMT BUIS (back up iron sight).
Barrel twist rate is also a consideration that needs to be addressed when setting up your rifle. 1/9 twist for lighter grain bullets (55gr. and below), and 1/7 twist for heavier ammo (62-77gr. ammo). The lighter grain ammo is cheaper to shoot, but the heavier grain ammo has better ballistic performance. If you decide on a 1/7 twist, you will need to get your upper from other than RRA (they only offer 1/9 barrels). For 1/7 twist barreled uppers: CMT/Stag (limited edition), LMT, Bravo company, Colt or a complete custom build are your options.
It is unlikely that you will find as many AR accessories for less money at your local gunshop as you will find here on the EE (equipment exchange) So look here first. I havent gone to my local gunshop to buy anything for my AR's in a long time
Keep in mind that it is usually cheaper to buy a complete rifle, but when you start to add/modify it to your liking, you will have some things that you will need to replace. (costing you more $ in the long run) If you have the money on hand, consider buying a complete lower from one of the many dealers who can build it to your specifications: stock options, grip options, sling mounting options etc... And then have the same done with your upper: handguard options, iron sight options, etc.
And dont forget magazines! Get USGI 30rounders with MagPul followers!!!
Good luck! And feel free to ask more questions before you buy!