Although you found him in Hall Co. in early 1800's, you need to understand how the North GA counties were formed during the mid-1800s. An overview is on the NE Regional GAGenWeb page. Further info about this should be on every county GAGenWeb page. This will probably explain to you why you are finding your PARKS in several counties....they didn't always move...it was the county lines that moved.
Take a look a Lumpkin Co., GA. I believe you'll find your Benj. Parks is the lucky man that discovered gold around Dahlonega and started the first US gold rush!!!