Dear Gary, I have not read the other answers, so forgive me if I'm repeating info you already know.....it doesn't cost you anything to have representation when working with a Builder, so I certainly suggest you get someone to assist you. The Builder's "rep" represents the Builder, not you. Having someone looking out for your best interests will hopefully give you some peace of mind, especially since you're new to the area. In addition, you'll want to know about warranties and taxes. And you should definitely have a home inspection. A Buyer's Agent can help with all of these.
Since you are paying cash, an appraisal is not necessary.......unless, of course, you want one for yourself. Having an attorney review anything in a real estate transaction is always recommended. Just make sure you use a real estate attorney. If you need a name, most of us can provide you one.
Best of luck, and welcome to Central Ohio!