Well, Shane, ain't we all!I'm afraid it isn't as easy as all that.There are (were) several lines of McGhee/McGee/McGehee/Magee (and many other spellings) 'in and through' TN beginning when TN was Western North Carolina -- except for the McG-ridden part (now E TN) that was claimed by Virginia.You will also find that wherever you find one family of McGs, you will find several -- not just that one family's siblings, but remnants of several other lines.
Start with the facts you have and list all the names and dates you have (Birth, death, marriages) and locations -- the who, when and where (include counties & towns if possible). Find out all the *facts* you can about your earliest known McGhees and their siblings and/or offspring. Then base your query postings on that data (read other posts, or look for posting guidelines, to learn how to write an effective query.)
You will find that spouses' names (if known), and the people's middle names, will become very important -- the naming conventions of the time often used the mother's maiden name as the middle name for one of the sons, and earlier generations of the mothers' parents' names for middle names.This can help you locate your people in the right family line.(This practice eventually fell out of use, but is still operating in the 1700s & 1800s.)
Go to www.TNGenWeb.org and begin reading the history of settlement in TN.It is VERY complicated.But you will need this understanding if you are going to research TN McGhees (however spelled).
Many of the McGs (my shorthand, so I don't have to write out all the spellings every time) started in early VA (some in MD), and went through NC, SC, and all the southern states (the Tennessee River route.)Some McGs went from NC through KY to the Cumberland River area (the route Boone route -- and yes, you will have to learn about the rivers, too, since they were the main means of travel until the railroads came in after the Civil War.)The Scotch-Irish McGees (mainly) came in through PA, and went all the same palces the others had -- but they also went into OH.This rough list takes you to about the early 1800s, when IN, IL, and lands west of the Mississippi began to open up -- then people begin showing up everywhere.
Also bear in mind that by about the 1840s another wave of Irish immigration began, and lots of Irish McGees begin showing up -- they came to work on canals and railroads.
Searching for McGhees is not an easy task.If you decide to take up the task, expect to be at it for a long time, and expect frustration.But you can learn a lot of history as you go.